Final report of the SAFEROAD project · 2018. 6. 19. · Final report of the SAFEROAD project | 2 Animals that cross the road may result in an unforgettable experience but more often

Safe roads for wildlife and peopleFinal report of the SAFEROAD project

Contents

1 Safe roads for wildlife and people 1

2 Legal requirements and policy targets for roads and wildlife 3

3 Outcome-basedspecificationsforroadmitigation 7

4 Road mitigation effectiveness 15

5 Cost-efficientroadmitigationstrategiesforwildlife 24

6 Roadmaintenancepracticestoimprovewildlifeconservationandtrafficsafety 33

7 Evaluatingroadmitigationperformance 39

8 Whatisnext? 47

SAFEROADDeliverables 49

Colophon 50

1 | Safe roads for wildlife and people

Chapter 1

Safe roads for wildlife and peopleRoadsandtrafficexertavarietyofdirect,indirectandmostlydetrimentaleffectsonwildlife.Roadsmaycausewildlifemortality,inhibitwildlifemovementsandresultinlossofhabitat orhabitatquality.InmostcountriesacrossEuroperoadagencieshaveacknowledgedtheirresponsibilitytocontroltheseimpactsanddevelopeffectiveroadmitigation.However, what is the best strategy to mitigate road impacts on wildlife? What mitigation measures can be seen as most effective? And how should maintenance practices be adapted to prevent impacts? Practitioners involved in road construction and maintenance need clear and practical guidelinestoimplementcost-efficientmitigationstrategiesandmaintenancepracticesthataimtoreduceroad-wildlifeconflicts.TheSAFEROADprojectwasstartedtoanswertothatneed.

TheSAFEROADprojectwascarriedoutin2014-2016aspartoftheCEDRTransnationalRoadResearch Programme Call 2013: Roads and Wildlife.ThefundingfortheresearchwasprovidedbythenationalroadadministrationsofAustria,Denmark,Germany,Ireland,Norway,Sweden,NetherlandsandUK.

TheaimoftheSAFEROADprojectwastoimproveour understanding of how and how effectively differentroadmitigationstrategiesworkinordertofindthebestwaytoreducetheimpactsofroads on wildlife and simultaneously enhance trafficsafety.Theprojectaimedtogeneratenewscientificknowledgeonandinsightsintomethodsto help prevent wildlife mortality due to animal-vehicle collisions and assure that the barrier effect ofroadsisreducedsufficientlytomaintainviablewildlifepopulations.Theaimwasalsototransferthisknowledgeintopracticalguidelinesandtoolsso it can be easily accessed and used by road agenciesandotherstakeholders.

Theresearchencompassedreviewsofscientific andnon-scientificpublications,explorationsofbest-practicesfromacrossEuropeandbeyond,re-analyses of existing data through meta-analysis in order to identify road mitigation effects that do not become obvious in the data analysis of a singleproject,collectionandanalysesofnewempirical data in a variety of case studies and analyses of mitigation effectiveness through populationmodelling.

TheSAFEROADprojectteamincludedbothscientistsandpractitioners.Hence,wewere able to address the questions of the CEDR researchprogrammescientifically,whileneverlosing sight of the practicality and feasibility of ourrecommendations.Wecollaboratedwithexpertsoutsideofourprojectteam,andevenoutsideofEuropetomakesurethatwecollectedandusedallofthestate-of-the-artknowledge andexperiencesavailablearoundtheglobe.Weincludedstakeholdersaswell,suchasprofessionals from road agencies and others that

Final report of the SAFEROAD project | 2

Animals that cross the road may result in an unforgettable experience but more often result in hazards for bothpeopleandwildlifeduetowildlife-vehiclecollisions.

dealwiththechallengesofroad-wildlifeconflicts,e.g.throughworkshopsandmeetingswherefeedbackwasprovidedonresearchapproachesordraftversionsofourdeliverables.

InthisreportwesummariseallofthefindingsoftheSAFEROADproject.Wehighlightkeymessagesand develop guidelines and illustrate these with examplesorcasestudies.Inaddition,weofferrecommendations on how to implement the findingsinroadmitigationpractice.Eachchapterin this report is based on one or more of the projectdeliverables.Thesesourcesarespecifiedattheendofeachchapter.Afulllistofthe

SAFEROADdeliverablescanbefoundonpage53.

TheSAFEROADprojectachieveditsobjectivesandidentifiedmitigationstrategiesandmaintenancepractices that are most effective in reducing road-wildlifeconflicts.Itprovidesdirectionforfuturemitigationworkstoensurebest-practicemitigationthatisbotheffectiveandcost-efficient.Hence,wehopetheprojectwillhelptoestablishasustainable green infrastructure across Europe as wellassaferoadsforbothwildlifeandpeople.


Chapter 2

Legal requirements and policy targets for roads and wildlife Howcancurrentenvironmentalpolicyandlegislationbetranslatedintoconcreteandmeasurabletasksforroaddevelopers?Whatdoesregulationactuallyrequire?Usingareviewoflegislationandinternationalagreements,courtcasesandimpactassessmentcases,wehave developed guidelines for the transport sector to better address wildlife barrier effects andmortalitytothebenefitofbothwildlifeconservationandroaddevelopment.

What is the problem?TheEuropeantransportsectorhasanimportantrole in controlling the negative impacts of roads andtrafficonnatureandwildlife.However,whatthis responsibility means in terms of requirements formitigationandcompensationisoftennotclear.EUenvironmentallegislationandpolicy,transposedintonationallegislationforEUmemberstates,hassetoverarchinggoalsfortheconservationofbiodiversity.Compliancewiththese legal provisions is a major challenge when designing new roads or operating and upgrading theexistingonesinEUmemberstates.Yetthesebroadlydefinedregulationshavetobetranslatedintomeasurabletasksforroaddevelopers.

Cost-efficientroadplanningandmanagementrequires all relevant manifest political goals to be unambiguous,widelyknownandtakenintoconsideration.ExistingguidancefromtheEUbuildsonlimitedcaselawanddatesbackto2006,hencenottakingintoaccountanyrecentcases.Due to this paucity of case law and limited

guidanceforconsentingauthoritieson,forexample,environmentalimpactassessment,therequired type and level of mitigation cannot be anticipatedbeforearoadprojectisstarted.Thiscomplicates the environmental assessment and mitigationofeffects,whichmaycausecostlydelaysintheplanningprocess.

Questions• What do current European laws and international

agreements state with respect to the barrier and mortality effects of roads on wildlife?

• Whatisthepractical,international(EU)levelofhow the legal incentives for mitigating barrier and mortality effects are addressed in road development projects?

• Are there any recent developments regarding requirements for mitigation and compensation in road building and maintenance that may affect this practice?

• Are there any unifying and separating patterns between countries regarding the assessing and mitigating barrier and mortality effects?


• What are the main shortcomings of current practice?Howcanshortcomingsincurrentpractice be overcome?

Our approachForthepurposeofthisstudy,wereviewedandanalysed:• EUDirectivesandotherinternational

agreements that we understood to be relevant to European species conservation and that refer to barrier and mortality effects of roads on wildlife.Wereviewedthemaintextsofthesedocumentsforpassagesonfauna,roads,environmentalliabilityandimpactassessment.We included available guidelines and additional documents referred to in the main texts in the review;

• recentcasesfromtheEUCourtofJusticeandfromthenationalSupremeCourtsofSpain,SwedenandtheNetherlandsaddressingwildlifebarriereffectsormortality,primarilyfromroadprojects,butrelevantcasesondevelopmentsother than roads were also included in the analysis;

• recentcasesoflargeroadEnvironmentalImpactStatements(EISs)fromSpain,SwedenandtheNetherlands.Welimitedthereviewtocasesaddressing barrier effects for wildlife or wildlife road-kill.

Thesearchforandselectionofcaselawproducedatotalof14casesforanalysis;EISsproducedanother14cases.AllcourtandEIScasesidentifiedwerereviewedforlegislation,speciesand effects addressed and the mitigating/compensatingmeasuresprescribed,followingastandardisedprotocol.

FindingsSome international regulations and agreements are of particular relevance in relation to barrier effects for wildlife and wildlife road-killTheHabitatsDirective,theBirdsDirective,theEnvironmentalLiabilityDirective,theEIADirective,theBonnConvention,theBernConvention and the European Agreement on Main InternationalTrafficArteriesallexplicitlyaddressthe conservation of species and set out

conservationobjectivesandresponsibilities,levelsofacceptableimpact,priorityspecies,principlesfor derogation and requirements for remedial action,researchandmonitoring.

Road-kill may be considered prohibited deliberate killingTheHabitatsDirective,theBirdsDirectiveandtheBernConventionprohibitthedeliberatekillingofspeciesofcommoninterest,whichincludesspecieslistedinthedirectives,inter alia all wild birds.Whatisdeliberateornotisamatterofcurrentdiscussion,butitisclearfromtheavailableguidelinesthatroad-killdoesnotautomaticallyqualifyasnon-deliberate.

Road projects must ensure that impacts on species are kept within acceptable levelsTheHabitatsDirective,theEnvironmentalLiabilityDirectiveandtheBonnConventionjointlysetanacceptable level of impact on species of common interest; any impact not jeopardising a ‘favourable conservation status’ and within the natural amplitudeofpopulationfluctuationscanbeconsideredacceptable.Afavourableconservationstatus requires that population dynamics data indicate that the species maintain itself on a long-term basis and that the range of the species isnotreduced.Ontheotherhand,theBirdsDirectivepointsatdifferent,possiblymoreambitiousgoals,i.e.maintainingallspeciesatlevelsneededtoprovideecosystemservices,expressedas‘ecological,scientificandculturalrequirements’.Alsonationalobjectivesfortrafficsafety and wildlife management may be more ambitious about the acceptable level of impacts andspeciesforwhichmitigationisneeded.

Ambitious mitigation and impact assessment may be enough to fulfil the provisions regarding protection of speciesWithregardtotheacceptablelevelofimpact,however,recentcaselawpointsinaslightlydifferentdirection.OneimportantEUcaseonroadimpactsontheIberianlynxandanumberofnational Supreme Court cases show that it may sufficeifaninfrastructuredeveloperadoptsahighambition level in mitigation and impact


assessmenttofulfiltheprovisionsoftheEUdirectivesontheprotectionofspecies.Thisimpliesthat,inadevelopmentprojectwherethebestavailable mitigation measures are applied and impactassessmentisreasonablywellconducted,the developer is relieved from the requirement to show that the impacts stay within acceptable levels; the burden of proof then lies with any party opposingthedevelopment.Availablecaselawcanthus be interpreted so that the requested conservation effort of a project can be described in terms of technical adaptations rather than populationstatus.

EU member states should conduct population-level monitoring and research on incidental killing of animalsAccordingtotheHabitatsDirective,EUmemberstates are obliged to establish a system to monitor theincidentalkillingofanimalsofcommunityinterest and conduct the research necessary to ensurethatincidentalkillingdoesnotsignificantlyimpactthespeciesćonservationstatus.Whiletheobligation for monitoring is not mentioned in the BD,itapparentlydoesnotincludebirds.TheEIADirective states that a developer of a major road projectisrequiredtodescribeimpactsonspecies,and the Environmental Liability Directive states that this should be done by means of measurable populationdatasuchas(i)numberofindividuals,densityorareacovered,or(ii)thespecies'capacitytoemigrateor(iii)thespecies'capacitytonaturallyrecoverorimmigrate.Theimpactsshould be assessed with reference to baseline conditionsandtakeintoaccountaspeciesńaturalpopulationfluctuations.

Applying the “1% criterion” to the toll from traffic mortality could facilitate impact assessment, but such an application is questionableAnotherpotentialimplicationforaroaddeveloper,althoughindicatedbyonlyoneDutchcase,isthepossibilitytoapplythe‘1%criterion’totrafficmortality.Thiscriterion,developedbytheEUORNIScommitteethatassiststheCommissionintheimplementationoftheBirdsDirective,statesthatanytollof≤1%ofthenaturalmortalityofthepopulationisnegligibleandthereforeacceptable.Whereas applying this criterion to road projects mayfacilitatetheimpactassessment,itappearswell out of the range of the application initially intendedandcorroboratedbyEUcourtdecisions.HencewequestionwhethertheDutchcasecanbeleadinginthatrespect.

EISs address barrier effects and habitat fragmentation, but generally underemphasise wildlife road-killThemajorroadEISsreviewedallexplicitlyaddressbarrier effects or habitat fragmentation and most

WarningsignstoalertdriverstothepresenceofIberianlynxinsouthernSpain.


ofthemdescribespecificfaunapassagesoradaptationsofexistingbridges,culvertsandtunnelsasimportantmitigationmeasures. Wildliferoad-kill,ontheotherhand,appears to be generally underemphasised as a conservationissue.

EISs generally fail to quantify the expected effects or differentiate between construction and operation phasesOnlyafewEISsdescribetheexpectedeffectsinquantifiedterms,whichisnecessarytobeabletorelatetoacceptablelevelsofimpact.Also,onlyafewoftheanalysedEISsdifferentiatebetweeneffects during the construction phase and the operationphase,whichmaytriggerdifferentrequirementsforpreventionandremedy.

Some country characteristics in impact assessments were observed, but may depend on method biasIncontrasttoSwedishEISs,SpanishandDutchEISsputmoreemphasisonavoidinganimaldisturbance.Moreover,DutchEISsstronglyemphasisebatmitigationmeasures.Requirementsfor monitoring appear to be particularly meagre in SwedishEISs.Weacknowledge,however,thattheapparent differences between the countries may dependonmethodbiases.

GuidelinesGuideline 1: Monitor wildlife impacts on population level and long-term, starting before construction Thisisbothanobligationandintheinterest oftheinfrastructuredeveloper.Therequirementsto assess impacts with reference to baseline conditionsandtotakeintoaccountaspeciesńaturalpopulationfluctuationsimplythatthepopulation dynamics of the species in question needtobereasonablywellknownandthatmonitoringshouldstartbefore,preferablywellbefore,theonsetofimpact.Otherwise,theassessment could become more limiting than whatismotivatedbyconservationgoals. Well- conducted monitoring should give a developer adequate room for manoeuvre

withoutjeopardisingthesegoals.

Guideline 2: Improve the assessments of disturbance, mortality and movement corridors, the quantification of impacts and the differentiation of construction and operation phasesToguaranteethatenvironmentallegalobligationsareachieved,EISscouldbeimprovedbybetteraddressing such issues as:• the effects of human disturbance on wildlife;• the impact of road mortality on wildlife conser-

vation;• the continuity of wildlife movements in the landscape(functionalmovementcorridors);

• the difference between impacts during construc-tion and operation phases;

• theexpectedeffectlevels(quantified).

Guideline 3: Apply best available mitigation measures – that may facilitate the consenting processStudying the ecological effects on the population levelisbothdifficultandexpensive,andifambitious mitigation indeed relieves the developer of the responsibility of proving that a proposed developmenthasnosignificantnegativeimpactsonpopulations,applyingbestavailablemitigationmeasures may facilitate the impact assessment and the consenting process and therefore be cost-effective.

Source: This chapter is a summary of SAFEROAD deliverable 1.

7|Saferoadsforwildlifeandpeople

Chapter 3

Outcome-based specificationsfor road mitigationNewtypesofcontractsinroadbuildingoftenresultinconstructorsnotonlybuildingbut alsodesigningthedesiredroad,includingmitigationmeasuresforwildlife.Thisimplies that procurement documents should no longer present detailed prescriptions on the technicaldesignofmitigationmeasures,butshouldprovidefunctionaldescriptionsof whatthemeasuresshouldachieve.Howtodefineoutcome-basedspecificationsthatcanguidecivilengineerstoproducefunctionalroadmitigation?HowtomakesurethatthesespecificationscomplywiththecurrentEUlegalandpolicyframeworks?Andhowtoimplementtheuseofoutcome-basedspecificationsintheprocurementprocess?

What is the problem?Asnationalroadadministrationsincreasinglymakeuse of contract types in which the constructor not only builds but also designs the desired roadorroadmodification,includingmitigationmeasuresforwildlife,anewsetofprocurementspecificationsisneeded.Procurementdocumentsshould no longer present detailed technical specificationsbutprovideoutcome-basedspecifications.Outcome-basedspecifications canbebestdefinedasspecificationsbasedonwhat providers will achieve rather than on what theywilldo.Thereasonthatmoreandmoregovernmental agencies are shifting to an outcome-based approach in procurement is the aim to delivermorevaluewithinconstrainedbudgets.Theapproachalsomeans-whichisoftenseenasanadvantage-thatriskmanagementbecomesmorearesponsibilityofthecontractor,whilesimultaneously the contractor gets more control andfreedomincarryingouttheproject.

Furthermore,itisassumedthatanoutcome-basedapproach provides a better breeding ground for innovationsandincreasescost-efficiencyover the more traditional contracting models with prescribedproductsorservices.

Outcome-basedspecificationsforthedesignandconstruction of road mitigation measures should haveaclearlinktothepredefinedobjectivesoftheroadproject.Intheirturn,theobjectivesof a road project will be derived from - national and international - obligations that result from environmental and transport legislation and regulations as well as ambitions elaborated in environmental and transport strategies and policies.Environmentalobjectivesultimatelyreferto improving or maintaining population persistence andconsequentlybiodiversityconservation.Inthisrespect,transportobjectivesrefertoimprovingroad safety and avoiding impacts on the natural environment,includingwildlife.Thechallenge


in an outcome-based procurement approach is to translate these objectives into clear and measurable functions that can be provided by roadmitigationmeasures.

Questions• Whatguidelinescanbeprovidedfordefiningoutcome-basedspecificationsthatcanguidecivilengineers in producing functional road mitigation measuresthatcomplywiththecurrentEUlegalandpolicyframeworks?

• Whatarethebenefitsofusingoutcome-basedspecificationsandwhataretherisks?

• Howcanoutcome-basedspecificationsbeimplemented in the procurement process?

Our approachWereviewedallrelevantEUenvironmentalandtransportlegislationandpoliciesandidentifiedwhattheymayimplyfordefiningoutcomesthatroadmitigationmeasuresmustprovide.Thefocuswas on road mitigation measures that aim to increase road safety and reduce road-related wildlife mortality and barrier effects that potentially reduce the survival probability of wildlifepopulations.Further,weanalysedtheoutcome-basedspecificationscurrentlyusedinroadmitigationprocurementintheNetherlands.We evaluated the extent to which these specificationsreflecttherequirementsoftheEUlegalandpolicyframeworksandthepotentialtolinkclearandmeasurableperformanceindicatorstotherequiredoutcomes.Usingboththeseanalyses and existing guidelines for the evaluation ofroadmitigationeffectiveness,wedevelopedasetofpracticalguidelinesfordefiningoutcome-basedspecificationsforprocuringroadmitigationmeasures and recommendations for implementation.Toillustratetheuseoftheseguidelines,weelaboratedtwopracticalexamples.

FindingsEU regulations and policies provide a variety of requirements and ambitions with regard to road projects that may help to define sound road mitigation outcomesInourreviewweidentifiedfourteenindicators(seetable),allofwhichprovidecluesfordefining

outcome-basedspecificationsforprocuringroadmitigationmeasures.Besidestheseindicators,thereview pointed out the importance of the measurabilityofeffects,bothfromactivitiesthatdamage the environment and activities that aim to mitigatesuchdamage,aswellastheuseofbaseline conditions or reference standards that allowforquantitativeevaluations.Usingindicatorsthatdirectlyrelatetoregulationsandpolicies,adopting a quantitative approach as well as incorporating clear baseline conditions or reference standardsindefiningoutcome-basedspecificationswill all inevitably improve the ability to judge whether or not performance requirements are beingmet.

The Dutch approach is feasible although there is room for improvementTheDutchnationalroadadministrationdevelopeda generic set of functional requirements that can best be seen as a gross list from which particular requirements can be selected that apply to the projectathand.Thespecificationsfocusonmaintainingorrestoringlinkagesbetweenwildliferangesatbothsidesoftheroad,hencerelating towildlifeoverpasses,wildlifetunnels,wildlifecrosswalks,bathop-overs,butalsotowildlifefences,habitatrestorationandotherlandscapingmeasuresthataccompanythecrossingstructures.ThespecificationsclearlyreflectsomekeyrequirementsandambitionsoftheEUlegal andpolicyframeworks;theystronglyrelatetorestoringlandscapeconnectivity,hence,theyclearlyreflecttheindicators‘habitatavailability’,‘habitatquality’and‘wildlifemovements’.Theemphasis is on restoring range and habitat connections that allow species to move through thelandscapeintheirnaturalway.Thus,theindicators ‘species distribution’ and ‘migration routes’arealsoimplicitlyaddressed.Improvementsmaybe(i)toincludeindicatorsthatrelatetopopulations;(ii)toputmoreemphasis on the impacts that need to be mitigated;(iii)toquantifytherequirements; (iv)tousebaselineconditionsorreferencestandards.Suchimprovementswillinevitably leadtoahigherpotentialtolinkthespecificationstoclearperformanceindicators.Currently,the


Indicator Environmental regulations Transport regulations EU Policies

HD BD ELD EIA BONN BERN MITA RISM BS GI SDS

Related to populations

Population viability X X X - X X - - X - -

Population size - X X - - X - - - - -

Population density - - X - - - - - - - -

Propagation capacity - - X - - - - - - - -

Related to species distribution

Actual distribution X - - - X - - - X X -

Historicaldistribution - - - - X - - - - - -

Related to species abundance

Actual abundance - - - - X - - - - - -

Historicalabundance - - - - X - - - - - -

Related to habitat

Habitatavailability X X - - X - - - X X -

Habitatquality X X - - - - - - X - -

Related to road barriers

Wildlife movements X - - - - - X - X X -

Migration routes - - - - X - - - - - -

Related to wildlife-vehicle collisions

Wildlife mortality X - - - - - X - X - -

Road safety - - - - - - X X X - X

ThetableshowstheindicatorsextractedfromEUenvironmentalandtransportregulationsandpolicies,whichprovidecluesfordefiningoutcome-basedspecificationsinroadmitigationprojects.Thetableprovidesanoverviewofwhetheradocumentmentionsanindicator(X)ornot(-).Legend:

HD=HabitatsDirectiveBD=BirdsDirectiveELD=EnvironmentalLiabilityDirectiveEIA=EnvironmentalImpactAssessmentDirectiveBONN=ConventionontheConservationofMigratorySpeciesofWildAnimals(”BonnConvention”)BERN=ConventionontheConservationofEuropeanWildlifeandNaturalHabitats(”BernConvention”)MITA=EuropeanAgreementonMainInternationalTrafficArteriesRISM=DirectiveonRoadInfrastructureSafetyManagementBS =EUBiodiversityStrategyGI =EUGreenInfrastructureStrategySDS =EUSustainableDevelopmentStrategy


procurement process in which functional specificationsareusedcanbebestdescribedas‘learning-by-doing’; projects and procurement procedures are continuously evaluated to assess whetherthefunctionalrequirementswereclear,complete and in line with the overall goal of the roadmitigation.Thisimpliesthatthegenericsetof functional requirements is permanently under development: as experiences and insights in what doesanddoesnotworkincrease,specificationsaremodified,addedordeleted.

The use of outcome-based specifications may have certain benefits if compared with the more traditional procurement approachesTheuseofoutcome-basedspecifications,basedontheseguidelines,mayhavevalueforallstakeholdersinvolved.First,theymaybetterensure that the overall objective - either related to wildlifeconservationorroadsafety-isbeingmet.Second,theymaysignificantlyincreaseourknowledgebaseassuchspecificationswillforceallinvolvedtogainmoreknowledgeonwhatdoesanddoesnotwork.Third,theymayguaranteeastronglinkwithnationalandinternationalregulations and policies and better support political and/or societal discussions on the need for and usefulnessofroadmitigation.Andfourth,anoutcome-based approach provides room for adaptivemanagement.Ifroadmitigationworks,designed and constructed on the basis of the best availableknowledge,appearinsufficienttoreachthedesiredoutcome,correctivemeasurescanbetaken.

The use of outcome-based specifications may have certain disadvantages and risks if compared with the more traditional procurement approachesFirst,suchspecificationsrequirebetterknowledgeon mitigation measures and their effects than whatwemayhavetoday.Thisimpliesthatcontractors may not yet be held fully responsible forafailureandthecostsofmitigationworksmayincrease.Second,costsmayincreaseduetotheneed for studies in which baseline conditions or referencestandardsareassessed.Third,littleisknownaboutappropriatetimespansforevaluation

studies,whichmayresultinwastingresourcesorwrong conclusions on whether or not the measures aresuccessful.Fourth,ifnotwellregulatedandsafeguarded,knowledgeonroadmitigationeffectiveness becomes an asset of private contractors and consequently may not be freely availabletoallstakeholders.Andfifth,anoutcome-based approach in road mitigation procurementrequiresanewjuridicalframeworkinwhich the responsibilities of both the road agency andcontractorsareclearlydelineated.

GuidelinesItisclearlyimpracticaltodevelopastaticsetoftechnicalrulesforroadmitigationworksthatmustalways be applied regardless of the actual conditions.Localandregionaldeviationsfromtherules may be necessary and render such a static systemofdesignspecificationsineffective.Instead,itmaybemoreefficienttodefinegeneralproperties or qualities that should be achieved to produce an outcome that meets the overall goals of mitigation as well as the requirements from environmentallegislationandpolicies.However,whatshouldsuchoutcome-basedspecificationslooklike?Howcanweensurethatsuchspecificationsresultintheendgoalsbeingmet?Andhowcanweavoidthesetofspecificationsbecomingtooextensive,whichmayreduceitspractical application?

Guideline 1: Link the specifications directly to the mitigation goalsNoprocurementofroadmitigationworksshouldbe started until the mitigation goals are clearly described.Thisgoesbeyondlistingtargetspeciesas it should include a clear description of what road impacts need to be addressed and to what extenttheseimpactsshouldbemitigated.

Guideline 2: Specify whether or not no-net-loss is the aimIngoalsforroadmitigationtwopotentialtargetscanbedistinguished:(1)no-net-loss,and(2)limited-net-loss.No-net-lossimpliesthatroadimpactswillbeentirelymitigated,i.e.,thepost-mitigation situation for the targeted species is identicaltothepre-roadconstructionsituation.


Limited-net-loss implies that a limited road impact willbeaccepted.Ifnotalreadydoneduringtheassessmentofmitigationgoals,thetargetlevelshouldbespecifiedinprocurement.Thedecisiononatargetlevelwilldependonthelocalsituation,including the local conservation status of a species,butmayalsobesuggestedbylegislation.

Guideline 3: Use the SMART-approach to develop clear and objective specifications Inoutcome-basedcontractsitisfundamentalthattherequired‘outcome’canbemeasured.Thisimpliesthat,forsuccessfuloutcome-basedprocurementarrangements,performanceindicatorsneedtobesetoutintheearlystages.Todoso,thespecificationsarepreferablySMART,i.e.Specific,Measurable,Achievable,RealisticandTime-framed.Roadmitigationgoals,andconsequentlythespecificationsformitigationworks,shouldideally:specifywhatroadimpact(s)is/are addressed; quantify the reduction in road impact(s)aimedfor;beagreeduponbyallstakeholders;matchavailableresources;andspecify the timespan over which the reductions in roadimpact(s)havetobeachieved.

Guideline 4: Make use of baseline conditions or reference standardsRoad mitigation measures can only be properly evaluatedifacleardefinitionofsuccesshasbeenformulatedinthedesignphaseoftheproject.Itwillnotbesufficienttoonlylisttheroadimpactsthatshouldbereduced,butthisreductionshouldalsobequantified.Forthispurposethespecificationsshouldpreferablymakeuseofeitherbaselineconditionsorreferencestandards.

Guideline 5: Link the specifications directly to the indicators used in regulations and policiesUnlikethemoreconventionalcontracttypes,outcome-based contracts articulate requirements in the form of end goals without specifying exactly howthesearetobeachieved.Theoverallendgoalof road mitigation is in line with the end goals of EUregulationsandpoliciesi.e.,preservingorrestoringbiodiversity,ecosystemsandecosystemservices.Inthisrespectitmakessensetolinkroadmitigationspecificationstotheindicators

derivedfromtheseregulationsandpolicyplans.Afterall,thiswillensurethatroadmitigationprojects correspond to the overall environmental objectives and allow better evaluations of whether road mitigation enforces the implementation of suchobjectives.

Guideline 6: Link the specifications to multiple indicators whenever possible and relevantOutcome-basedspecificationswillgaininstrengthifmultipleindicatorsareaddressed.Forexample,iftheroadmitigationaimstoreduceroadkillandincrease the road permeability of a vulnerable wildlifepopulation,thespecificationsshouldpreferably include requirements that relate to wildlife-vehiclecollisions,roadbarriereffectandpopulationviability.If,inthiscase,thespecificationsfocusonlyonroadkillandallrequirementsarebeingmet,populationsurvivalmaystillbeinjeopardyasaresultofinsufficientwildlifemovements.

Guideline 7: Link the specifications to the road section to be mitigated and not to a single structure Theexactnumberandplacementofcrossingstructures are preferably not decided upon in advance,butarepartoftheprocurementarrangement.Bothnumberandplacementstrongly affect the performance of mitigation works;hence,ifthesefactorsaredeterminedinadvance,potentialcontractorswillhavelessroomfor innovations and designs may be less differential.Infact,linkingspecificationstoindicators that relate to populations or species distribution may become impossible as the number andspatialdistributionofstructuresarekeyfactors for achieving the pre-set goals for such indicators.

Guideline 8: Keep the use of technical specifications to a minimumAlthoughtechnical-ordesign-specificationscanbeincluded,theiruseshouldbekepttoaminimumastheyinhibitthefunctioningofariskandrewardspaymentmodel.Forexample,ifafunctionalrequirement(e.g.‘90%reductioninroad-kill’)iscombinedwithatechnical


Box3.1 Example1:Toadontheroad

A local road crosses toad habitat and separates theirlandhabitatfromtheirbreedingponds.Hence,thetoadshavetocrosstheroadtwiceayear,duringspringmigrationandwhentheyreturntotheirlandhabitatafterbreeding.Eachyear,especiallyinspring,manytoadsarekilledona1-kmroadstretchduetotraffic.Thepopulation size is still considerable but shows a negativetrend.Topreventthedeathsoftoadson the road and a further decrease of population numbers,theroadagencyinitiatedaroadmitigationproject.Theambitionistoinstallanumber of crossing structures that should bring thetoadssafelyacrosstheroadandkeepthepopulationhealthy.Thefollowingsetofoutcome-basedspecificationsmaybeproposed:

1 Themitigationmeasureswillallowatleast90%ofthemigratingtoadstogetacrosssafely.

2 Themitigationmeasureswillensurethatnomore than 5% of the migrating toads will be killedintraffic.

3 Themitigationmeasureswillensurethatthesurvival probability of the toad population is >99%calculatedovera100-yearperiod.

4 Themitigationmeasureswillbeineffectyear-round.

5 Themitigationmeasureswillmeettherequirementsofspecification1to4inthefirstyearafterinstallation.

6 Themitigationmeasuresandpopulationwillbe monitored for a period of 5 years to determinewhetherspecifications1to4arebeingmet.

Amphibiantunnels(top)arefrequentlyinstalledtohelptoadssafelyacrossroadsduringspringmigration(bottom).

specification(e.g.‘constructfences1.5mhigh’),the contractor can no longer be held responsible when the functional requirement is not met in the end.Further,technicalspecificationsdonotstimulate innovations and evaluations in which mitigationperformanceisassessed.Technicalspecificationsmaybeusedforstructuresorstructural features that are considered ‘non-negotiable’.Forexample,specificdimensionsforastructure can be included if there is a comprehensive body of proof that a structure of

suchdimensionsisfunctional.Nevertheless,aregularcheckisneededtodeterminewhetherthetechnicalspecificationsusedarestillstate-of-the-art.

ImplementingtheguidelinesTheuseoftheseguidelinesisillustratedbytwohypotheticalexamplesofroadmitigationprojects.Thefirstexampleaddressesthemitigationofaroadwherelargenumbersoftoadsarebeingkilledduringspringmigrations,andconsequentlythe


survivalofthelocaltoadpopulationisatstake(Box3.1).Thesecondexampleaddressesthemitigation of a road on which moose is frequently killed,andconsequentlyroadsafetyisinjeopardy(Box3.2).

Toimplementtheuseofoutcome-basedspecificationsintheprocurementofmitigation

worksitisrecommendedto:(i)makesurethatenvironmental authorities are closely involved in the procurement process in order to ensure that environmentalobjectivesareadequatelyreflectedinthecontract;(ii)developagenericsetoffunctionalspecificationsthatcanbeeasilyadaptedto the situation and ambitions of the project at hand;(iii)writeoutcome-basedspecificationina

Box3.2 Example2:Mooseontheloose

Ahighwaycrossesmoosehabitat.Suitablefeeding areas occur on both sides of the highway and hence moose are crossing the road frequently.Overthepastfiveyearstenmoose-vehicle collisions occurred on average each year ona4-kmstretchofthehighway–hereafterreferredtoasthe‘hotspot’.Allcollisionsresultedinthedeathoftheanimal,butonlyafewcaused human injuries; one collision resulted in ahumanfatality.Thepopulationsonbothsidesoftheroadaresufficientlylargeandnotseriouslyaffectedbythenumberoftraffic-relatedanimaldeaths.Moosemovementsacrossthe highway also occur elsewhere but they rarely result in accidents outside the collision hotspot due to differences in road design and the presence of bridges and tunnels that moose useforsafepassage.Toincreaseroadsafety,the road administration initiates a mitigation project.Theambitionistoimplementmeasuresthatwillkeepthemooseofftheroadandreducethenumberofcollisions.Thefollowingsetofoutcome-basedspecificationsmaybeproposed:

1 Themitigationmeasureswillreducethenumber of moose-vehicle collisions at the collisionhotspotbyatleast80%,comparedto the mean number of collisions at the hotspotoverthepastfiveyears.

2 Themitigationmeasuresatthehotspotwillnot cause an increase in the number of moose-vehicle collisions on adjacent high-waystretcheswithoutmitigation,comparedto the mean number of collisions at these stretchesoverthepastfiveyears.

3 Themitigationmeasureswillbeineffectyear-round.

4 Themitigationmeasureswillmeettherequirementsofspecification1to3inthefirstyearafterinstallation.

5 Themitigationmeasureswillbemonitoredfor a period of 5 years to determine whether specifications1to3arebeingmet.

Mitigating road stretches where moose cross frequently arevitaltoguaranteeroadsafety.


language style similar to that of technical specifications;(iv)developaclearsetofperformance indicators that accompany the outcome-basedspecifications;(v)contractanindependent contractor to evaluate the road mitigationworksonthebasisoftheperformanceindicatorsprovided;(vi)developastrategytosystematically assess baseline conditions and referencestandards;(vii)developanopenaccessdatabase on road mitigation evaluations so that future projects will be able to learn from previous ones;(viii)evaluatetheuseofoutcome-basedspecificationsinroadmitigationprocurementascomparedtotheuseofdesignspecificationsandgatherempiricalevidenceonthepossiblebenefitsand/ordisadvantagesoftheapproach.

Further,werecommendcarefullytestingtheguidelines presented here in practice as well as a genericsetoffunctionalspecificationsthatcanbe

derivedfromthem.Ifdeemedappropriateaftertesting,theguidelinesshouldbemodifiedtooptimise their application in road mitigation projectsthroughouttheEU.



Chapter 4

Road mitigation effectivenessThereisgrowingevidencethatroadsandtrafficreducethepopulationsofmanywildlifespecies.Overthelastfewdecadesconcernfortheimpactsofroadsonwildlifehasresultedintheinstallationofnumerousmitigationmeasures.Dotheywork?Aretheyeffectivelypreventingroad-killandenhancingmovementofwildlifeacrossroads?Whatlessonscanbederivedfromexistingworkstooptimisefuturemitigation?

What is the problem?Thedetrimentaleffectsofroadsonwildlifehavebeenextensivelystudied.Roadsandtrafficmaycause mortality of wildlife due to wildlife-vehicle collisions,actasbarrierstoanimalmovementandmigration and affect both the amount and quality ofwildlifehabitat.Consequently,roadspotentiallyjeopardise the long-term persistence of wildlife populationsoreventhesurvivalofaspecies.

Over forty types of road mitigation measures intended to reduce road effects on wildlife have beenimplementedordescribed.Theseincludemeasures that: • influencemotoristbehaviour,suchaswildlifewarningsigns,animaldetectionsystems,measurestoreducetrafficvolumeand/orspeedand temporary road closures;

• scare animals away from the road and/or alert themtoapproachingtraffic,suchaswildlifereflectors,mirrorsandrepellents;

• increase the attractiveness of areas away from theroad,suchastherestorationofsaltlicksorwater holes;

• decreasetheattractivenessoftheroad,suchascleaning up grain spills;

• introduceaphysicalbarrieralongtheroad,such

as fencing; • createsaferoad-crossingopportunities,suchascrosswalksandwildlifecrossingstructures(under-oroverpasses).

Roadagenciesfacethechallengeofmakinginformeddecisionsonwhichmethodtouse.Although practical issues have to be considered in suchdecisions-e.g.,availablebudget,hindertotrafficduringconstruction,necessarymaintenanceafterinstallation,publicsupport-knowledgeofthe effectiveness of each type of road mitigation shouldbethekeycriterion.Afterall,ifallpracticalissues are accounted for but the mitigation goals arenotreached,themitigationmaynotonlywastefinancialresourcesbutmayalsocreatetheunjustimpressionamongstakeholdersthattheproblem has been solved and further measures arenotneeded(Box4.1).Consequently,wemayendanger the viability of wildlife populations or eventhesurvivalofspecies.


Questions• What road mitigation measures were found to be effectiveinreducingroad-killorenhancingroadpermeability?

• What guidelines can be provided to help road planners in preparing a mitigation plan?

Our approachWe assessed the effectiveness of road mitigation measures through a literature review and meta-analysis.Inadditionwecarriedouttwoempiricalstudies,oneintheNetherlandsandoneinNorway,toillustratetheimportanceandbenefitsofproperinformationonmitigationperformance.

Theliteraturereviewfocussedonbothroad-killand barrier effect mitigation and aimed to assess (1)whatmitigationmeasureshavebeenevaluatedfortheirperformance;and(2)theextenttowhich

themitigationreducesroad-killorimprovesroadpermeabilityforwildlife.Thefocuswasonpeer-reviewedpublicationsinwhicheitheraBefore-After-Control-Impact(BACI),Before-After(BA)orControl-Impact(CI)studydesignwasused.

Themeta-analysisfocussedonroad-killmitigationandaimedtoestimate(1)theextenttowhichroad-killmitigationeffectivenessdiffersamongmeasures;(2)theextenttowhichtheeffectiveness of particular road mitigation measuresdifferamongtaxa;and(3)theextenttowhichstudydesigninfluencestheestimatedeffectivenessofroadmitigationmeasures.

We used the outcome of both reviews and the empirical studies to develop a set of practical guidelinestoselectappropriatemitigation.Theseguidelinesshouldbeseenasachecklistthathelps

Box4.1 Economyversuseffectiveness

Economicconsiderationsstronglyinfluencethechosenmitigationmeasure.Comparativelyinexpensivemeasures-e.g.,warningsigns,wildlifereflectors,whistlesorrepellents-arecommonly employed by road agencies despite there being little evidence concerning their effectiveness.Forexample,warningsignsareperhaps the most common mitigation measure implemented across the world to reduce large animalcollisionswithvehicles,yetmany

transportation and natural resource agencies reporttheydidnotknowwhetherthismeasurewaseffective.Incontrast,measuresthatarethoughttobemoreeffective-i.e.,wildlifefencing,crossingstructuresandanimaldetection systems for large mammals - may not be implemented due to high costs and low public support.Wherecostsratherthaneffectivenessdrivesdecision-making,mitigationeffectivenessmaybecompromised.

Warning signs are one of the mostly used type of road mitigation although there is little evidence that they effectively reduceroadimpacts.


to address all relevant issues in preparing an effective road mitigation plan based on the current knowledgeofwhatworksandwhatnot.

FindingsResults literature reviewThenumberofstudiesaddressingtheeffectiveness of road mitigation on wildlife in Europeisratherlimited,consideringthefact that in many European countries road mitigation measures have been implemented for over twenty years,andinsomecaseforoverfortyyears.Fifteenscientificstudiesfromeightcountries wereidentifiedthataddressedtheissueofroadmitigationeffectiveness.Thesestudiescontain50datasets,withmoststudyingasinglespeciesandmitigationtype(37datasets);some(13datasets)reportedtheeffectsofmultipletypesofmitigationmeasures,theeffectsformultiplespeciesorspeciesgroups,oreffectsassessedbyusingdifferenttrialtypesorresponsevariables.Thestudiesaddresstencategoriesofroad

mitigation:wildlifewarningsign,in-vehiclewarning,wildlifereflector,chemicalrepellent,acousticrepellent,wildlifefence,crossingstructure,wildlifefenceandcrossingstructure,speedlimitenforcementandreducedtrafficvolume.

In16datasets(32%)noresponse,oronlyatemporaryresponse,tothemitigationmeasureswasdetected.In20datasets(40%),mitigationmeasureshadapositiveeffect,i.e.reducingroad-killorincreasingroadpermeability.In8datasets(16%),mitigationmeasureshadanegativeeffect,i.e.increasingroad-killorreducingroadpermeability.Sixdatasets(12%)concernedresponse variables that may potentially affect road-killandroadpermeabilitybutwerefarremovedfromtheassessmentendpoint,i.e.theeffectonroad-killorroadpermeability;forexample,measuringchangesinvehiclespeedorbehaviouralresponsesoftheanimals.Inthesedata sets responses were measured that may

Relationship between weighted-mean effect sizes and the weighted-mean percentofroad-killreductionamonglargemammals for three different types of mitigationmeasures.Theeffectsizeisastatistical measure based on the difference in standard deviation units between the means of the control sites (orbefore-monitoringperiod)andimpactsites(orafter-monitoringperiod).Apositive effect size indicates a reduction in road-killwiththeroadmitigationandanegative effect size indicates an increase inroad-killwiththeroadmitigation.Valuesinbracketsarethenumberofeffectsizeestimates.Errorbarsindicate95%confidenceintervals.


resultin:aroad-killreduction(3datasets),onlyatemporaryroad-killreduction(2datasets),orroad-killincrease(1dataset).

For each study an ‘evidence score’ was assessed on the basis of six criteria that relate to the scientificqualityofthestudy.Studiesreceiveda100%scoreiftheywererandomised,replicated,controlled,includedbefore-aftertrialswithpaired-sites and there was no need to exptrapolate from measured response variable to the assessment endpoint.Themeanevidencescoreofthefifteenidentifiedstudieswasrelativelylow(28%).Currently,therefore,evidencefortheeffectivenessof road mitigation is not only limited because of a relatively small number of studies but also because of limitations in the inferences that can bemade.

Fences are the best option for reducing the road-kill of terrestrial faunaIngeneral,themeta-analysisshowedthatmitigationmeasures(alltypes)reduceroad-kill(alltaxa)by40%comparedtocontrols.Fences,withorwithoutcrossingstructures,reduceroad-kill(alltaxa)by54%.Nodetectableeffectonroad-killwasfoundofcrossingstructureswithoutfencing.Withintaxa,largedifferencesmayoccurbetweenmitigationmeasures.Forexample,thecombination of fencing and crossing structures led toan83%reductionintheroad-killoflargemammals,comparedtoa57%reductionforanimal detection systems and only a 1% reduction forwildlifereflectors.

Comparatively expensive mitigation measures (e.g., fences with crossing structures) reduce large mammal road-kill much more than inexpensive measures (e.g., reflectors)Whilemanufacturersoftenclaimthatreflectorsareascientificallyprovenmethodforreducingdeer-vehiclecollisions,forexample,theirlong-termeffectivenessisrarelyconsidered,androadplannersshouldnottaketheseclaimsatfacevalue.Simultaneously,manyofthemoreexpensivemeasures(e.g.animaldetectionsystems,crossingstructureswithassociatedfencing),haveshownhighreturnsoninvestment,

withtheongoingbenefitsexceedingtheircostsovertime.Overall,whenchoosingamitigationmeasuretoreduceroadmortality,roadagenciesshouldconsiderthecost-benefitofthemeasuresthat go beyond unfounded assumptions on the functionalityofthesemeasures.

There are insufficient data to answer many of the most pressing questions that road planners ask about the effectiveness of road mitigation measuresBasedonthecurrentliteraturemanyquestionscannotbeanswered,suchaswhetherotherlesscommonmitigationmeasures(e.g.,measurestoreducetrafficvolumeand/orspeed)reduceroadmortality,whatmitigationmeasuresaremosteffectiveforsmalltomedium-sizedmammals,amphibiansandreptiles,andbirds,ortowhatextent the attributes of crossing structures and fences,forexample,influencetheireffectiveness.Thestudyalsorevealedthatmanyroadmitigationevaluations could not be included in the analyses duetothelackofbaselinedataonpre-mitigationconditionsand/orlowsamplesize.Therefore,werecommend that studies incorporate data collection before the mitigation is applied and that they use a minimum study duration of four years forBAandeitheraminimumoffouryearsorfoursitesforBACIstudydesigns.

GuidelinesHerewepresentasetoftenguidelinestohelproadplannersdecideonmitigationmeasures.

Guideline 1: Elaborate clear goals of mitigationThepointofdepartureforanymitigationplanshouldbethegoalsofmitigation,includingadescriptionofthetargetspecies.Moreover,thegoalsshouldanswertotheSMARTapproach,i.e.theyshouldbespecific,measurable,achievable,realistic,andwithacleartimeframe.Roadmitigation goals should ideally: specify what road impact(s)is/areaddressed;quantifythereductioninroadimpact(s)aimedfor;beagreeduponbyallstakeholders;matchavailableresources;andspecify the timespan over which the reductions in roadimpact(s)havetobeachieved.Inpractice


the descriptions of the mitigation goals are often lessspecific;theyshouldfirstbeelaboratedaswithout clear goals no decisions can be made upon the most favourable approach in mitigating road effects.

Guideline 2: Derive the need for provisions that restore road permeability from measured or predicted population level barrier effectsMitigationthatrestoresconnectivity,suchascrossingstructures,crosswalksortemporaryroadclosures,isneededwhenwildlifepopulationsareproven or expected to be affected by barrier effects.Inthemitigationofanexistingroad,measured barrier effects should direct decisions on crossingmeasures.Inmitigationinassociationwiththeconstructionofanewroad,predictedbarriereffectsshouldbethekeycriterionindecisionsoncrossingmeasures.Suchpopulation-level barrier effects are diverse and may include (1)areductioninpopulationsizeand,

consequently,adecreaseinpopulationviability;(2)areductioninmovementsandgeneflowbetweenpopulationsand,consequently,anincreasedriskofgeneticdeficiencies;(3)abarriertoaccessingkeyhabitatandconsequentlyaffecting,forexample,fitnessandreproductivesuccess;and(4)abarriertoaccessingnewhabitat and consequently slowing down colonisationsandpopulationgrowth.Population-levelbarriereffectscanalsobeindirect,forexample when the road is a barrier for a species thathighlyaffectsthelifecycleofotherspecies.

Guideline 3: Select road mitigation types whose effectiveness has been provenForwideusewithinroadprojects,onlythosemeasures should be selected that have convincingly been shown capable of reducing the barrier effect of roads and/or road-related wildlife mortalities.Thisrequireswellperformedevaluations of the effectiveness of road mitigation

Estimatesofwildlifecrossingratesatcrossingstructuresmayhelptoinferpopulationsurvivalprobabilities,althoughsuchestimatesdonotdirectlyanswerthequestionoftheextenttowhichtheimpactsoftheroadandtrafficonwildlifehavebeenmitigated.


measures,including(1)comparisonsbetweenimpactsites(i.e.,siteswheremitigationmeasuresareinstalledormodified)andcontrolsites(i.e.,sites where a road is present but there is no mitigationormodification);(2)datacollectionbeforethemitigationisapplied;(3)replicationinspaceandtime;and(4)randomisationofimpactand control sites across the pool of potential study sites.Ifscientificsupportforeffectivenessislacking,themeasuresshouldnotbeapplied.Ifinnovativemeasureshavebeendeveloped,werecommend thoroughly testing them using a high-quality experimental approach before applyingthemwidelyinroadprojects.

Guideline 4: Include wildlife fencing if road-kill reduction is the aim, but combine fencing with wildlife crossing structures to prevent fence-induced barrier effectsFencing has been proven to be essential in reducingroad-kill,inparticularforlargemammals.Whilea100%road-killreductioninlargemammalsisrarelyreachedthroughfencing,themeasureissignificantlymoreeffectivethan,forexample,animaldetectionsystems.Thereislittleor no evidence in the literature that mitigation measures aiming at affecting driver or animal behaviour,suchaswarningsignsandwildlifereflectors,reduceroad-kill.Thesemeasuresshould no longer be applied until their effectivenesshasbeenproven.Itisbestpracticeto always combine wildlife fencing with safe crossing opportunities for wildlife to ensure connectivitybetweenhabitats/ecosystems.Cosntructing crossing structures without associated fencing should not been seen as an effectivemeasuretoreduceroad-kill.

Guideline 5: Select a fence type that addresses the requirements of all target speciesThereisnoonefits-allapproachinfencing.Eachtarget species should be considered in decisions onfencelength,heightandmaterial.Theclimbingorburrowingabilityofanimalsshouldalsotakenintoaccount.Forexample,fencesshouldbemodifiedwithtopextensions,orbuiltwithasmoothverticalsurface,topreventanimalsfrom

climbingoverthem,orthebaseofthefenceshouldbeburiedorincludeaskirttopreventanimals from digging under and breaching the fence.

Guideline 6: Base the road length over which fencing is needed on road-kill or species distribution data and account for potential fence end effectsDecision on fence length should be carefully made onthebasisofthelocalsituation.Inthecaseofmitigationofanexistingroad,road-killdataofthetarget species should direct decisions on fence length.Inthecaseofmitigationinassociationwiththeconstructionofanewroad,noroad-killdataexists,anddetaileddistributiondataofthetargetspeciesshouldbethekeycriterionindecisionsonfencelength.Ifsuchdistributiondataislacking,thepresenceofpotentiallysuitablehabitatforthetargetspeciescanbeused.Fencingshouldnotjusttakeplaceatroadstretcheswhereroad-killoccursorisexpected,butshouldbecontinued beyond these stretches to prevent fence endeffects,i.e.elevatedroad-killimmediatelyadjacenttofenceends.Thedistanceoverwhichfencing should be continued depends on the target speciesandthelocalsituation.Asarule-of-thumbmean daily movement distances of the species can be used to decide on fence length beyond the road stretchwhereroad-killoccursorisexpected.

Guideline 7: Select measures that create crossing opportunities in which the requirements of all target species are taken into accountEach target species should be considered in decisionsontype,designandpositioningofcrossingmeasures.Inthisrespectitisessentialtohave information on the acceptance and use of different types and designs of crossing measures by the target species as well as the conditions these species prefer in the direct surroundings of thecrossingmeasures.Thisdoesnotimplythatallcrossing measures should facilitate all target species.Forexample,ifamitigationprojecttargets two species and one of them needs one crossingstructureandtheotherneedsthree,onecrossing structure can be selected that facilitates


bothspecies,whilethetwootherstructurescanbe selected solely on the basis of the needs of the secondspecies.

Guideline 8: Base the density of crossing measures on the mitigation goals Themitigationgoalsshouldrefertobothtargetspeciesandtheroadeffectstobemitigated.Withthesegoalsasastartingpoint,thedensityofcrossing measures can be assessed on the basis of empirical data on the mean distance over which

crossing measures can be reached by each target species(Box4.2and4.3).

Guideline 9: Select types of mitigation measures that have proven to be sustainableSome mitigation measures tend to show failures onlyfewyearsafterinstallation.Clearexamplesare small crossing structures and fences for amphibians,reptilesormammals.Suchfenceseasilygetbroken,andsmallcrossingstructureseasilygetfloodedorblocked-up.Thisimpliesthat

Box4.2 Tunnelsfortoads

Oneofthelargestcommontoad(Bufo bufo)populationintheNetherlandsisbisectedbyatwo-laneroad.Inthepast,highnumbersoftoadswerekilledbytrafficduringspringmigration,astheanimalshadtocrosstheroadtomigratefromtheirwinteringhabitat(southoftheroad)totheirbreedingponds(northoftheroad).Until2010volunteersputuptemporarydrift fences and pitfall traps to catch the migrating animals and transported them manuallyacrosstheroad.In2010thetemporary measures were replaced by two amphibian tunnels and permanent drift fences alonga1-kmroadstretch.Duringspringmigrationsin2013,2014and2015toadsthattriedtocrosstheroadwerecaptured,individuallymarkedandreleasedatthespotwheretheyhadbeencaptured(Ottburg&VanderGrift,inprep).Useoftheamphibiantunnelswas monitored with the help of a pitfall at the northerntunnelexit.Asthepermanentdriftfences did not prevent all toads from entering theroad,theroadsweresurveyedfortoads,deadoralive.Theresearchersfoundthatonaverageonly31%ofthemarkedtoadsusedthetunnels.Theothersendedupontheroad(1%)or quit following the drift fence before a tunnel wasreached(68%).Theminimumestimateofthe average distance covered by the toads along thedriftfenceswas67m.Therefore,itwasrecommended to increase the number of tunnels

as the current tunnel density did not create sufficientroadpermeabilityfortoads.

Markedtoadsalongthedriftfence(top)andcapturedinthepitfallatoneofthetunnelexits(bottom).


Box4.3 Spacingofcrossingstructuresformoose

InNorway,fencesarebuiltalonghighwayswithhightrafficvolumeandhighspeedlimitstoavoidanimal-vehiclecollisions.Often,crossingstructures are built to provide animals with the opportunitytocrossthesefencedroads.Thesecanbestructuresdesignedforwildlife,multiplepurposesortraffic.Rolandsenetal.(inprep)studiedhowmanyandwhatkindofstructuresareneededformoose(Alces alces)toreachpre-setmitigationgoals.Forthispurposetheyanalysed the movements of 55 moose that had beenfittedoutwithaGPS-collar.Thestudysuggests that moose use wildlife crossing structures with a higher probability than crossinganunfencedroadwithhightrafficvolume.Formulti-useandtrafficstructures,however,nosignificantlyhigherprobabilityis

found for using a structure as compared to crossinganunfencedroadwithhightrafficvolume.Whenthedistancetothewildlifecrossingstructuresincreased,thelikelihoodofmoosechoosingtousethestructuredeclined.Forwildlifecrossingstructures,theresultssuggestthatbuildingastructureevery1.4kilometreswouldoutweighthebarriereffectofthe fence: Moose use such spaced crossing structures with the same probability as crossing anunfencedroadwithhightrafficvolume.

FemalemoosemarkedwithGPScollarandeartags.


such measures need frequent inspection and maintenance.Itisthusbettertoemphasiseconstructing more robust fences and wildlife crossingstructures.Forexample,amphibianfences made of concrete are more sustainable thanthosemadeofplastic.Andlargewildlifeover-orunderpasseswillnotbeeasilyblocked-up

orflooded.Higherconstructioncostsarebalancedbylowercostsofmaintenanceandareducedriskoffailure.

Source: This chapter is a summary of SAFEROAD deliverable 8, 9, 10, 11, 13 en 14.

Synthetic amphibian fences tend to show failures a few yearsafterinstallation(top).Concrete barriers are a sustainablealternative(bottom).


Chapter 5

Cost-efficientroadmitigation strategies for wildlifeInmanywildlifespecies,thetransportsectorhasaspecialresponsibilityforavoidingorreducingtrafficmortalityandformaintainingorrestoringconnectivityacrossinfrastructurebarriers.Approachestoachievethesegoalsaremany,butonlyafewareeffectiveandeconomicallydefendable.Howcanmortalityandbarriereffectsbemitigatedinacost-effective way? Which of both impacts should be given priority? When and where should mitigationbemandatory,andhowmuchimpactcanbetoleratedfromaneconomicorecological point of view?

What is the problem?Millions of mammals and birds perish every year onEuropeanroads,andthelossofotheranimalgroupsisinnumerable.Statisticsareratherpoorandincompleteandrefermostlytolargerspecies,especiallygamespecies,inwhichcultural,ethicalandeconomicinterests,legalobligationsor,aboveall,trafficsafetyconcernsprovidereasonstoreportaccidents.Largemammalsinparticulararethe targets of many road mitigation projects for wildlifeinEurope.Exclusionfencesandwildlifecrossing structures are typically designed to meet the requirements of these species or to increase trafficsafety,whilebenefitstootherspeciesarewelcomedbutoftennotnecessarilymandatory.

Eachyear,collisionswithlargewildlife,especiallyungulates,costbillionsofeurosinsocio-economiclosses,thousandsofinjuredpeopleandseveraldozensofhumanfatalities.Despitedecadesofpreventionattempts,collisionstatisticsindicateasteadyincreaseinnumbers.Thequestionthusarises of whether mitigation investments have so farbeeninsufficientorineffective.Moreroadsmay

needtobefencedagainstwildlifeinthefuture,but fences are expensive and alternative measures tokeepwildlifeoffroadshavenotyetproveneffective.Fencingalsoentailssecondaryproblemsthatmaytriggertheneedforadditionalmitigation.Forexample,alongfenceincreasesbarriereffectson wildlife and may require installing special crossing facilities that allow animals to move betweenpopulationsandhabitats.Shortfencesmayonlydisplaceaccidentriskstowardsfenceendsandthusevencompriseatraffichazardiftheseendsarenotsecured.Gapsandopeningsinfences will inevitably allow animals to enter the fencedroadcorridor,withtheconsecutiveriskofcausingaccidentsorincreasingwildlifemortality.

Butevenwithoutfences,busyroadscanimposefunctionalbarrierstowildlife.Smallspeciesmaybe unable to cross the road as they avoid spaces withoutcover,andlargerspeciesmayavoidattempting to cross roads because of the dense traffic.Wheremanybusyroadscrisscrossthelandscape,meshesintheroadnetworkmayeventually become too small to support local


populations or even individuals to survive or to be managedsustainably.

Fencesandcrossingfacilities,i.e.barrierstoprevent mortality and passages to prevent isolation,arethustwosidesofthesamecoinwithwhichroadmitigationforwildlifecanbeachieved.Thechallengeistodecideonhowmuchofeitherorbothisneededinagivensituation,foracertainspeciesorwithalimitedbudget.

Questions• Howcanmortalityandbarriereffectstowildlife

be mitigated in a cost-effective way? Which measures are reliable and robust and which haveapotentialforbeingthis,iffurtherdevel-oped?

• Which of both impacts should be given priority? Are there differences between species and between situations?

• Howmuchmitigationisneededordesiredtomeet national and international objectives on speciesconservation,environment,androadsafety? Are there other objectives that can motivate mitigation?

• Whatknowledgeisstillmissingtodeveloporimplement optimal mitigation solutions? Where and what type of research is needed to produce thisknowledge?

Our approachWecombinedliteraturereviews,analysesofempirical accident data and simulation models to study general relationships for four types of ‘species’-non-responder,pauser,speederandavoider(seegraph)-andcreatescenariosthatcanhelpindecidingonmitigation.Westudiedtheinfluenceofenvironmentalfactorsrelatedtolandscape and road design on the spatial distributionofwildlife-vehiclecollisions.Thiswas

WarningtodriversandconsequentspeedreductionneartheendofwildlifefencesinSweden.


doneinthreecasestudies,inSpain,SwedenandNorway,allrelyingonthegeographicalanalysesofpolice-reportedungulate-vehiclecollisions(UVC).

Combiningthesefindingswithinformationfromscientificandtechnicalliteratureandpracticalexperiences of road administrative personnel with both wildlife-vehicle collisions and the costs and efficaciesofmitigationmeasures,wedevelopedasimpletoolforcost-benefitevaluationandproposed a simple strategy to address mitigation planning.

We then developed a road permeability model to simulatetheeffectofroadnetworksandmitigation efforts on the viability of wildlife populations.Themodelallowedforthestudyofspecificgeneraltraitsinanimalbehaviourorthe

degreeoflandscapefragmentation.Thesimulationmodel was parameterised using results from previousstudiescombinedwithexpertopinions.

FindingsRoad mitigation for wildlife should primarily focus on reducing mortality and secondly on providing permeabilityOursimulationmodelsstronglysuggestthat,inmostconditions,populationviabilityismoredependent on the survival of individuals than on migrationabilities.Migration,i.e.thepermeabilityofroadnetworks,isofsignificancewhenpopulations are small and the movements of individuals are large relative to the mesh size of theroadnetwork.However,animalspeciesdifferin their area requirements and response to road traffic.Mitigationapproachesmusttherefore

Graphillustratingtherelevanceofroadtrafficonmortalityandbarriereffectsonspecieswithdifferentresponsestotraffic.Animalsthatdonotrespondtotrafficatallwillbekilledmoreoftenastrafficvolumeincreases,whilespeciesthatavoidcarsmaysufferlessfrommortalitybutbeincreasinglyrepelledfrombusierroads.Bothspecies,however,mayexperienceasimilaroverallbarriereffect.BasedonJacobsenetal.(2016).


consider these differences and target barrier or mortalityissuesappropriately.

A significant part of traffic-induced mortality in wildlife occurs on rather few locations in the road networkClustersinUVCmaycontainbetween20-40%ofallreportedUVC,butcoveronly1-2%oftheroadnetwork.Thisimpliesthatratherlimitedbutwell-targeted mitigation efforts can substantially reduceaccidentnumbers.

UVC clusters can be explained by and predicted from a combination of landscape and road factors operating primarily on a local scaleTheselocalfactorstypicallyrelatetoeitherroadaccessibilityorroadattractiveness.Accessibilityreferstothepresenceofphysicalbarriers,i.e.mainlyexclusionfencesandsafetyrails,andpartly

also to the landscape elements that may funnel anddirectanimalmovementstowardsroads.Attractivenessisamorecomplexproperty,involvingthepresenceofforageandcover,e.g.,road verge vegetation and garbage containers in SpainorshrubsandtreesinSwedenandNorway,as well as the animals’ need to access resources ontheothersideoftheroad.

Inclusive fencing systems appear as the most effective albeit relatively expensive mitigation approachSuch fencing systems combine wildlife fences with escaperamps,electrifiedmats,gridsorgatestosecurefenceopenings,warningsystemstoalertdrivers approaching fence ends and safe crossing facilitiesforwildlife.Well-designedandproperlyinstalledsystemscanreduceUVCbyover90-95%,ensuresufficientpermeabilityandstillbecost-effectiveinmanyifnotmostUVCclusters.

WildlifedetectionandautomateddriverwarningatacrosswalkinSweden.


Vehicle speed and traffic volume are further important factors for the spatial aggregation of UVCOnaverageUVCclustersoccuronbusierroadswith higher speeds than accidents that are not clustered.Localandtemporaryreductionsofspeedmayhenceprovidepowerfulmitigation. Thiscanbeachievedthroughinstallingon-sitewarning systems triggered by animal-detection systems,throughin-carGPS-basednavigationtools that alert drivers when entering a road sectionwhenrisksarepredictablyhighorthroughacombinationofboth,i.e.aGPSalertactivatedbyanimalpresenceneartheUVC.

A significant part of UVC is, however, rather randomly distributed across the road networkIfUVCarewidelydispersedalongroadsandnotclustered,theycannotbeappropriatelyaddressedbylocalmitigationsuchasfencingsystems.Instead,mitigationeffortsmustaimatfactorsoperatingon“global”scales,suchastheabilityofthedriverorvehicletorespondtoanimalsintime.Relevant mitigation options may be found in intelligent in-car animal detection and driver assistance systems that may automatically adjust vehiclespeedorshortenreactiontime,butalsoindrivereducation,probablybasedonrisk-prediction models that can teach drivers to identify riskysituationsandadoptpreventativedrivingbehaviour.HowmuchthesemitigationapproachesmaybeabletoreduceUVCisnotyetknown.

Cost-benefit analysis for mitigation against UVC will always underestimate the potential benefitsCost-benefitanalysis(CBA)isausefultoolandshould be employed more often in mitigation planning;however,themainchallengeisassessingthepotentialbenefitsofreducingUVCovermanyyearsinthefuture.Thesocio-economiccostsofUVCaresubstantialbutstronglyunderestimatedduetothepresentfocusontraffic-safetypolicy.AsfewUVCentailhumaninjuryordeath,mostcostsforUVCrelatetomaterialdamagesandlostvaluesforwildlife.Benefitsmustthereforeincludenotonly costs of human injuries or material damages inaccidents,butalsotheoverallcostsof

managingthisconflict,aswellasconsumptiveand non-consumptive and non-monetary values of wildlife that cannot be appropriately monetised andmustthereforebeintegratedintoCBAviapolicyobjectivesorlegalrequirements.

Mitigating wildlife-vehicle collisions can produce significant socio-economic benefitsEvenifonlythemonetisedbenefitsareconsidered,ourstudiessuggestthathighsocio-economicbenefitscanbegainedfromatargetedapproachatUVCclusters.Accidentsoccurringoutside clusters require other mitigation approaches that still need further development andresearch.Althoughsomeobstaclestoeffectiveimplementation may result from inadequate technicalsolutions,manymoreprobablyresultfromthelackofdata,limitedknowledgeandinappropriatepolicy.

GuidelinesGuideline 1: Develop a multi-stakeholder policy on mitigation for wildlifeRoadmitigationofwildlifeconflictscannotbedonesolelybytheroadagency;severalstakeholdersandactors must be involved in developing and implementingmitigationapproaches.Together,theymustdevelopquantifiablemitigationobjectivesthatcanbeusedtomotivateimplementation,directfurther development of mitigation and monitor the overallprogress.SuchgoalscanbeexpressedasX%reductionincollisionnumbersduringYnumberofyearsandbespecificforthetargetspecies,regions,typesofaccidentsorrespectivestakeholderresponsibilities.Multi-stakeholderstrategies may involve the installation of inclusive fencingsystemswithgreenbridges,tunnelsorcrosswalks,dependingontrafficconditions,combined with adjusted land use plans on vegetation,plantationandwildlifemanagement,aswell as driver education methods and enhanced in-cardriverassistancesystems.

Guideline 2: Acknowledge the full costs of wildlife-vehicle collisions or traffic related mortality in wildlifeExistingcoststandardsforroadaccidents(thattypicallyonlyconsiderhumaninjuryanddeath)


need to be updated and complemented by estimatesofmaterialdamages,administrativeandmanagement costs and the lost values of wildlife (consumptiveandnon-consumptivevalues).Benefitsthatcanbegainedorsavedthrougheffective mitigation are generally underestimated andincomplete.Clarifywhichcostsareincludedinacost-benefitanalysisandwhicharenotmonetised and thus must be considered in policy targets.

Guideline 3: Improve empirical data on mortality/collisions and establish reliable and long-term geo-referenced statisticsReliable and extensive empirical data is essential toplanningandevaluatingmitigation.Ifnotalreadyexisting,developareliablereportingsystemforroad-killedanimalsthatatleastfocuses on the most relevant species from an ecological,economicorotherstakeholderpointofview.Areportingsystemcanbebasedoncitizen-

Fencesareonlyeffectivewheninstalledproperlyandregularlymaintained.Whenanimalsaretrappedinsideafencedroadcorridor,theriskofaccidentssignificantlyincreases.


science approaches or derive from standardised inventories,policereportsorroadmaintenancerecords.Estimatesofthespatialandnumericalaccuracy of these statistics must be made and correction factors should be developed for extrapolation to the assumed real number of accidents.Accidentstatisticsshouldbepubliclyavailable,withaccidentpositionsandclustersvisualisedonmaps.Calculatedescriptivestatisticsthatmaybeusedforregionalbenchmarkingandmonitoringoftheoverallmitigationsuccess.

Guideline 4: Develop a targeted mitigation approach to reduce wildlife-vehicle collisions along identified accident clustersCombine the above geo-referenced accident data and results from cluster analyses with estimates of accident costs to map the most costly roads wherelocalroadmitigationmaybecost-effective.Employcost-benefitanalyses,comparedifferentmitigationalternativesandrankpotentialmitigationsiteswithrespecttotheircost-benefitratioandtheireffectonpolicytargets.Wherestaticandlong-terminstallationsareplanned,suchasgreenbridgesorwildlifetunnels,involveotherstakeholdersanddevelopajointstrategy to ensure the future effectiveness of the proposed measures.Thesestatisticsandtrafficandlandscapedatacanproduceriskpredictionmodelsthat can be updated automatically and used in driverinformationsystems.

Guideline 5: Ensure the proper monitoring and evaluation of mitigation activities and initiate experimental studiesDevelopscientificallysoundmonitoringschemesand employ follow-up studies as a standard in mitigation.Initiateandallowforexperimentalstudies on mitigation alternatives that may be evaluatedusingtheabovemonitoringschemes.Produce annual status reports based on mitigation efforts,monitoringresultsandaccidentstatisticsdescribedabove.Thiswillincreaseevidence-basedknowledgeandfosterthedevelopmentofinnovative and probably more cost-effective approaches.

Guideline 6: Initiate cooperation with stakeholders and support research on innovative approachesCooperation is highly advisable between road administrationsandmanyotherstakeholdersthatcanengageintheresearch,developmentandevaluationofmitigationmeasures,especiallythosethataddressglobalandlandscapescales.Support research on both fundamental questions inwildlife-vehiclecollisions,theirspatio-temporalpatternandsocio-economiccosts,andondeveloping applications such as model-based driver-warning systems or in-car animal detection systems.

Source: This chapter is a summary of SAFEROAD deliverable 3, 4, 7 and 12.


Objective Responsibility Scale Target Mitigation approach Function Pro’s Con’s Overall judgement

to separate animals and traffic

TransportAdministration and Road Agency

road,local animal fence tokeepanimalsofftheroadandleadthem to safe passages

highlyefficientifdoneand designed appropriately

expensive,riskofmalfunction,barriereffects,requiresadd-ons

most advisable if combined with crossing facilities

repellents to repel animals from approaching the road

presumably cheap no proven effect not advisable

reflectors,acousticsignals to warn or scare animals when cars approach

presumablycheap,teachingeffectonanimals

inconclusive evidence notadvisableyet,furtherresearchrequired

animal &driver

verge management toreduceattractivenessofroadverge,increase detectability

possible positive side effects on overall trafficsafety

requiresfrequentmaintenance,inconclu-sive data

partiallyapplicable,furtherresearchneeded

driver speedreductionto50km/h to increase driver response time overallbenefittotrafficsafety,reducedbarrier effects

increased travel time produces high costs

highly advisable if temporary

trafficcalming/rerouting to reduce occasions for collisions reducedoverallimpactonwildlife,fewerbarrier effects

limitedapplicability,onlydislocatesproblem

applicable with restrictions

Landowner,Hunters,Municipality

landscape animal population control to reduce the abundance of animals near the road

on a large scale presumably effective ineffectiveonasmallscale,lossofwildlife and ecological values

only advisable on a large scale

habitat management to reduce the abundance of animals near the road

presumably long-lasting effects possibleeffectonlanduseproductivity,sensitivetochangesinlanduse,untested

further research needed

Driver,Companies,Public

global + local

driver education toincreaseriskawarenessandinflu-ence driving behaviour

generalspin-offontrafficsafety individualityinresponses,lowoveralleffectiveness

further research and technical develop-ment needed

active in-car warning to inform drivers when they enter a high-riskroadsectionduringhigh-risktimes

evidence-based,concreteandrelevantinformation

individualityinresponses,yetuntested further research and development needed

driver assistance systems to assist drivers in detecting animals andbrakingintime

in-carsolutions,reliable,likelyafuturestandard anyway

yetuntestedforWVC,presumablynotsufficientinhigh-speedtravel

further research and development needed

to maintain animal mobility


road,local driver local speed reduction to 50 km/h

to increase driver response time and reduceaccidentrisks

overallbenefittotrafficsafety,reducedbarrier effects


conflictswithtransportpolicy,furtherresearch needed

animal gap in fence with static speed reduction

to funnel movements to safer crossing placesandseparateanimalsfromtrafficin time

cheap,simple requiresspeedcameras,riskofaccidentsif speed limit not obeyed

advisable,furtherresearchneeded

crossing structures toseparateanimalsfromtrafficpermanently

highefficacyifdonewell,multi-purposeuse,long-termeffect

expensive if built only for wildlife mostadvisable,existingstandardsmaybe optimised

animal &driver

crosswalkwithanimaldetection and driver warning


provenefficacy,verylimitedeffectontraffic

technicallysensitive,applicabletosmaller roads only

highlyadvisable,furtherresearchneeded


landscape animal habitatmanagement,GreenInfrastructure

to divert animal movements parallel to or away from the road to safe crossing locations



supplementalfeeding,salt,water,etc

to reduce the animals’ need or motiva-tion to move across the road

presumably long-lasting effects possibleeffectonlanduse,inconclusiveempirical data


Tablesummarisinganevaluationofroadmitigationmeasuresforwildlife.Measuresaregroupedaccordingtoobjective,target,responsiblestakeholderandspatialscale.


Objective Responsibility Scale Target Mitigation approach Function Pro’s Con’s Overall judgement

to separate animals and traffic


road,local animal fence tokeepanimalsofftheroadandleadthem to safe passages

highlyefficientifdoneand designed appropriately

expensive,riskofmalfunction,barriereffects,requiresadd-ons

most advisable if combined with crossing facilities

repellents to repel animals from approaching the road

presumably cheap no proven effect not advisable

reflectors,acousticsignals to warn or scare animals when cars approach

presumablycheap,teachingeffectonanimals

inconclusive evidence notadvisableyet,furtherresearchrequired

animal &driver

verge management toreduceattractivenessofroadverge,increase detectability

possible positive side effects on overall trafficsafety

requiresfrequentmaintenance,inconclu-sive data

partiallyapplicable,furtherresearchneeded

driver speedreductionto50km/h to increase driver response time overallbenefittotrafficsafety,reducedbarrier effects


highly advisable if temporary

trafficcalming/rerouting to reduce occasions for collisions reducedoverallimpactonwildlife,fewerbarrier effects

limitedapplicability,onlydislocatesproblem

applicable with restrictions


landscape animal population control to reduce the abundance of animals near the road

on a large scale presumably effective ineffectiveonasmallscale,lossofwildlife and ecological values

only advisable on a large scale

habitat management to reduce the abundance of animals near the road



Driver,Companies,Public

global + local

driver education toincreaseriskawarenessandinflu-ence driving behaviour

generalspin-offontrafficsafety individualityinresponses,lowoveralleffectiveness

further research and technical develop-ment needed

active in-car warning to inform drivers when they enter a high-riskroadsectionduringhigh-risktimes

evidence-based,concreteandrelevantinformation

individualityinresponses,yetuntested further research and development needed

driver assistance systems to assist drivers in detecting animals andbrakingintime

in-carsolutions,reliable,likelyafuturestandard anyway

yetuntestedforWVC,presumablynotsufficientinhigh-speedtravel

further research and development needed

to maintain animal mobility


road,local driver local speed reduction to 50 km/h

to increase driver response time and reduceaccidentrisks

overallbenefittotrafficsafety,reducedbarrier effects


conflictswithtransportpolicy,furtherresearch needed

animal gap in fence with static speed reduction


cheap,simple requiresspeedcameras,riskofaccidentsif speed limit not obeyed

advisable,furtherresearchneeded

crossing structures toseparateanimalsfromtrafficpermanently

highefficacyifdonewell,multi-purposeuse,long-termeffect

expensive if built only for wildlife mostadvisable,existingstandardsmaybe optimised

animal &driver

crosswalkwithanimaldetection and driver warning


provenefficacy,verylimitedeffectontraffic

technicallysensitive,applicabletosmaller roads only

highlyadvisable,furtherresearchneeded


landscape animal habitatmanagement,GreenInfrastructure

to divert animal movements parallel to or away from the road to safe crossing locations



supplementalfeeding,salt,water,etc

to reduce the animals’ need or motiva-tion to move across the road

presumably long-lasting effects possibleeffectonlanduse,inconclusiveempirical data



Chapter 6

Maintenance practices to improve wildlife conservation and trafficsafetySeveralconflictsbetweenroadsandwildlifecanpotentiallybeavoidedthroughtheapplicationofpropermaintenancepractices.Wildlife-vehiclecollisionshaveproventobestronglyrelatedtothemanagementofvergesandotherroadfeatures.Whatmaintenancepracticesthataddressroad-wildlifeconflictsarecurrentlybeingused?Whichofthesepractices seem promising? What guidelines can be provided for improving road maintenance practicestoenhancewildlifeconservationaswellastrafficsafety?

What is the problem?Road operators are increasingly aware about wildlifeissues,probablyduetotheriseinwildlifehazards,particularlyungulate-vehiclecollisions,but also because of the need to maintain the numerous wildlife mitigation measures that have been implemented and the environmental regulations that require greater protection of habitatsandspeciesinhabitingroadsides.

During the last twenty years the attention paid to the effects of roads on wildlife has increased notably.Avastnumberofwildlifecrossingstructures and other mitigation measures have been constructed on roads all around Europe since thefirstEuropeanhandbook‘WildlifeandTraffic’in2003waspublishedbytheCOST341Action.Wildlifecrossingstructures,togetherwithproperlymanagedroadverges,retentionpondsandotherroadsidehabitats,havebeenrecognisedbytheEuropean Commission as potential elements of the ‘GreenInfrastructure’inEuropethatcanplayan

importantroleinwildlifeconservation,particularlyinintensively-managedlandscapes.However,asaconsequenceoftheglobaleconomiccrisis,budgets for road infrastructure maintenance have declined.Consequently,identificationofstrategiestooptimisethecosts-benefitsratioofroadmaintenance investments has become a priority as well as the effectiveness of the measures that aim toreduceroad-wildlifeconflicts.

Questions• What maintenance practices are currently being

used and which of these practices show high potential in preventing or mitigating road-wildlife conflicts?

• What guidelines can be provided for improving road maintenance practices to enhance wildlife conservationaswellastrafficsafety?

Our approachToinvestigatecurrentmaintenancepracticesandtoidentifyopportunitiestoimprovethem,we


interviewed 24 professionals involved in road maintenance from 11 European countries and reviewed technical documents about road maintenance.Aworkshopthatbroughttogetherengineers and wildlife experts to discuss how road maintenancecouldbeimprovedforthebenefitof

wildlifeandtrafficsafetywasorganisedalongtheIENEConference2014and,finally,theanalysiswas complemented by a literature review to gather evidence-basedknowledgethatcouldbeusedtodetermine best practices and provide new guidelines.

FindingsExisting guidelines and handbooks provide only brief and mostly general recommendations for the maintenance of wildlife-related issuesFencing and roadside vegetation management are includedinallroadmaintenanceguidelines,butoftenwithnoparticularfocusonwildlifetopics.Ontheotherhand,handbooksaboutdesigningwildlife mitigation measures usually pay little attentiontomaintenanceissues.However,draftingguidelines that address wildlife-related maintenance(suchasroadvergesandlandscapedareasmanagement)isincreasingandcanbeseenasapositivetrend.Insomecases‘Roadvergesmanagement plans’ or ‘Wildlife management guidelines’areprovidedforasingleroad,thusallowing maintenance to be properly adapted to localroadfeaturesandenvironmentalconditions.

Most wildlife mitigation measures are regularly inspected and repaired, but the lack of inventories and specifications of standards to be accomplished make it difficult to undertake appropriate maintenanceFencing,wildlifewarningsigns(includingtemporarysigns),roadverges,drainagesystems

and wildlife crossing structures are the road elements that are commonly inspected and maintainedbyroadmaintenancestaff.Maintenance schemes vary widely among countries and regions and differ according to road features,trafficcapacityandregulationsaswellasin relation to environmental conditions in the surroundinglandscape.Regularinspectionsmainlyfocus on structural rather than on functional conditions,andbudgetrestrictionsreducethemaintenanceactivitiesundertaken.Inadequatemanagement of wildlife mitigation measures has beenpointedoutasthecauseoffailuresandlackofeffectiveness.However,maintenanceandenvironmental follow-up conducted on new motorways for 3 to 5 years is common practice in many countries and allow an appropriate maintenanceatleastduringthisperiod.

Applying maintenance practices to enhance biodiversity in roadside habitats is increasing throughout Europe. However, in many countries verge maintenance strategies focus only on reducing large-mammal hazards to traffic safetyMost actions aim to control alien invasive species andtobenefitendangeredfloraandsmallor

Flowchart of our approach to develop guidelines for road maintenance

Interviews24 road maintenance professionals from11 countries

Current road maintenance related to wildlife: strengthsandweaknesses

Technicalandscientificliterature review

BestMaintenancePracticeidentification

Workshop WildliferoadmaintenanceGuidelines


aquaticfauna.Usuallythesepracticesarecarriedoutinsensitive,protectedareas,suchasroadscrossingNatura2000sitesorendangeredspecies’habitats.Providingrefugesorrestingplacesforbats,birdsandothersmallanimals(e.g.dormouseorpollinatorinsects)iscarriedoutinmanycountries,particularlyonnewmotorways.InMediterraneancountries,fireriskisabigconstraintonvegetationmanagement.Ahighdensity of prey such as rabbits in verges or voles in medians is seen as a wildlife hazard in many sites because predators are attracted to areas with ahighmortalityrisk.

Animal-vehicle collisions involving large animals and traffic victims are registered all over Europe by traffic police. Nevertheless, the results are rarely reported to road operators and, when available, data accuracy is often poor and not applied to define mitigation measuresBestpracticesforanimal-vehiclecollisions(AVC)registrationarefoundinScandinaviancountries,where moose-vehicle accidents cause a major conflict;AVCdataarecompiledinintegrateddatabases with the participation of several stakeholders.ThelackofGPS-basedtoolsforgeographicalprecision,ofstandardiseddatacollectioncriteria(includingspeciesidentification)andofwildlifetrainingoffieldstaffcollectingthose

dataarethemainreasonforpoordataaccuracy.Accurate data could provide a good basis to identify road stretches where clusters of wildlife-vehicle collisions are registered and to design and evaluatemitigationmeasures.

Evaluating the effectiveness of maintenance practices is key to identifying and expanding the most cost-effective practices, but such evaluations are only reported occasionallyThecollectionandanalysesofenvironmentalandwildlife data allows the effectiveness of wildlife mitigation measures and habitat management practicestobeevaluated.Thedefinitionofthresholds above which mitigation measures must beappliedisnotacommonpractice.However,road operators apply mitigation measures such as installing wildlife warning signs or fencing in road sections where clusters of accidents involving animalsareregistered.

The stakeholders conducting road maintenance vary according to the road management system, which can be public or operated in public-private partnershipThevastmajorityoftheroadnetworkisapublicasset,butpublic-privatepartnership(PPP)managementisarisingpracticeacrossEurope.Providing standard prescriptions about wildlife-related issues to be included in contracts to

Placingwildlifewarningsignsisoneofthemostcommonactivitiesundertaken.Temporarysignsrequirehighermaintenancethanstandardones,butallowadaptationtotheriskperiodandreducetheriskofadriver’shabituation.


operator and maintenance companies is reported tobeacrucialtooltoquicklyimprovewildlife-relatedissuesmanagement.Insomecountriescontractsalreadyaskforecologyexpertstobepart of the inspection staff and/or training on wildlifeissuesisprovidedtomaintenancestaff.

GuidelinesGuideline 1: Standards on wildlife-related topics must be included in general Road Maintenance Guidelines to allow a proper maintenance of wildlife provisions Guidelinesshouldincludeinformationabouthowto inspect and maintain roadside habitats and wildlife mitigation measures and must allow or evenencourageanadaptationtolocalconditions.Such standards must provide detailed information toroadoperationstafftoguaranteethattasksareproperlyundertakenandfocusnotonlyonstructural features but on all conditions to guaranteetheirlong-termfunctionality.

Guideline 2: Wildlife maintenance actions should be adequately planned and prioritised to enhance their cost-benefit ratio Maintenanceshouldbeundertakenonthebasisofclearprescriptionsandchecklistsofpointstobeinspected.Inventoriesofallinstalledwildlifeprovisionsanddetailedspecificationsofstandardsto be accomplished are needed to develop a propermaintenanceplan.Multiuseofcrossingstructuresisanincreasingpractice,butwherehumanandfaunausesarecombined,differentandmorecostlymaintenancetasksmaybenecessary.However,costscanbelimitedthroughprovidingclearregulationsandinformation.Wildlifefencesmustbemanagedtoprovidetrafficsafety but also to funnel animals to safe crossing points.Vegetationbesidefencesmustbemaintained in such a way that the structures are not damaged and opportunities for animals to get ontotheroadareavoided.Adaptingfencestoeach target species may largely improve their

Properly managed retention ponds may be valuable habitats for aquatic species but require appropriatemaintenancetoreduceaquaticfaunamortality.


effectiveness.Monitoringisneededtoensurethananadaptivemaintenancestrategyisapplied.

Guideline 3: Road managers can favour biodiversity conservation and Green Infrastructure development by conducting wildlife-friendly roadside habitat management Some examples of maintenance activities to be conductedtopromotebiodiversityare:(i)removing alien invasive species that could damage localhabitatsorspecies,(ii)creatingsuitablehabitats for pollinators on verges and other green areasinhighlyanthropogeniclandscapes,(iii)managing road verge vegetation to avoid high densities of prey in sites where they could attract predatorstohighriskroadsidesor(iv)creatingrefuges for small and aquatic fauna in drainage systemsorretentionponds.Somepracticeswillalsobenefithumansbyprovidingecosystemservicessuchaspollination.However,attractinganimals to roadsides could also create ecological traps,increasetheroadmortalityofendangeredspeciesand,whenlargeanimalsareattracted,

couldincreasethehazardstotrafficsafety.Propermaintenance practices play a relevant role in preventingthesenegativeeffects.

Guideline 4: Animal-vehicle collisions should be accurately monitored to assess where conflict points are located and to evaluate which mitigation measures are most effective Web-based databases and other smart technologies will help to achieve the goal of compiling and evaluating all the information about wildlife mortalityandotherwildlifeobservations.Accurateregistration of road casualties by road maintenance patrolsisafirststeptobeachieved,butthecooperationofotherstakeholders(trafficpolice,roadusershunters,etc.)isstronglyrecommended.Regularstandardisedanalysesofroad-killandtheuse of thresholds for applying mitigation measures areneededtotakedecisionsaboutwhichmeasuresneedtobeappliedtoreduceconflicts.Thesedatamay also allow the evaluation of the effectiveness of the overall mitigation strategy in a road project oraroadnetwork.

Adaptiveroad-wildlifemaintenancestrategy.

Innovative solutionsNew findings

Modificationof Road-Wildlife management practice

InspectionMaintenance

Registering data

Road-WildlifeManagement Planning

StandardsandGoals

ComplianceMonitoringAssessment

Proper conditions and standards are achieved

ImprovingMaintenancepractices

Conflicts


Guideline 5: Develop and monitor an adaptive road-wildlife maintenance strategyAn adaptive road-wildlife maintenance strategy should include: drafting standards for wildlife mitigationmeasures,tobemetaccordingtotheinstructions provided by designers and constructors on road safety and operation requirements; schedulinginspectionandmaintenancetasksadapted to the local conditions of wildlife and habitats; establishing procedures for identifying conflictsortheirdeviationandhowtoproceedtosolvethem;definingpropertrainingprogrammesformaintenancecrews;anddefiningproceduresformonitoring and reporting compliance with standards,anddisseminatingthisinformationtoroadplannersandotherstakeholdersinvolved.

Guideline 6: Cooperation between stakeholders is needed to ensure an information flow during the entire road lifecycle A lifecycle approach will provide excellent opportunities to improve wildlife mitigation measures and to identify the best strategies for wildlife-roadmaintenance.Roadauthoritiesshould

bethelinkbetweenallstakeholdersthroughouttheroad’slifecycle.Providingstandards,goalsandoutcome-basedspecificationsforwildlifemitigationmeasures could help road authorities to supervise maintenance or operator contractors and ensure compliance.Measurableindicatorsandthresholdswill be helpful to determine when a practice must beimproved.

Guideline 7: Cooperation with external stakeholders will benefit wildlife-road maintenanceCollaboratingwithotherstakeholders,suchasownersofsurroundinglands,NGOs,environmentalagenciesandresearchcentres,isachallengingissue.Cooperationwillcontributetoensurelong-term mitigation and to improve the effectiveness of mitigationmeasures,likewildlifecrossingstructures,andreducewildlifeconflicts.Collaborationwithotherstakeholderscanalsocontributetodatacollectionforcost/benefitanalysesofon-goingmanagementprogrammes.


Cooperationagreementswithlandowners,conservationorganisationsandotherstakeholderscouldprovidevaluablehelpforroadsidehabitatsmaintenance.Asanexample,suitablegrazingmayhelptocontrolvegetationgrowthonroadverges.


Chapter7

Evaluating road mitigation performanceInmanycountriesroadmitigationforwildlifehasbecomecommonpractice.Nowadays,inprocuringmitigationmeasuresashiftcanbeseenfromdesignspecificationstooutcome-basedspecificationsinwhichdesiredfunctionsaredescribed.Suchatransitiondemandscarefulevaluationsoftheperformanceofroadmitigation.Whatisthebestwaytodothis?Which performance indicators should be selected? What would be the best study design to assess whether the desired outcome is achieved? And how can we be assured that the measured outcome is not biased by factors that do not directly relate to the road mitigation works?

What is the problem?Road mitigation performance evaluations have been an important means to increase our knowledgeofwhatmitigationworksandwhatdoesnot.Theyhavebeencrucialtoassesswhethermeasurestakenresultinaimed-forreductionsinroadimpacts.Morerecently,suchevaluations also became essential in procuring mitigationworks.NationalroadadministrationsincreasinglymakeuseofDesign&Constructcontractsinroadbuilding.Inthesecontracts, the constructor not only builds but also designs thedesiredroadorroadmodification.Althoughsuch contracts are not yet widely used to constructmitigationmeasuresforwildlife, some road agencies are experimenting with theseprocurementapproaches,andthereseemsto be increasing interest in shifting to such approaches.

Thisshiftimpliesthatprocurementdocuments no longer present detailed prescriptions on the technical design and dimensions of road mitigation measures,e.g.wildlifecrossingstructuresorwildlifefences,butprovidedescriptionsofwhatthemeasuresshouldachieve,i.e.,whatthe

outcomeshouldbeofthedesiredmeasures. Itisthetaskofthecontractortotranslatetheseoutcome-basedspecificationsintotechnicalsolutions and to prove that the solutions are functional.Withsuchatransitionfromdesignspecificationstooutcome-basedspecificationsforroadmitigationmeasures,newapproachesareneeded to assess whether the outcome aimed for hasindeedbeenachieved.

Questions• What guidelines can be provided to evaluate

road mitigation conformance with outcome-basedspecifications?

• What recommendations can be provided to implement these guidelines?

Our approachTodevelopguidelinestoevaluateroadmitigationperformance,weusedthestate-of-the-artknowledgeonconductingscientificallysoundevaluations,includingrecentpublicationsonhowto evaluate road mitigation functioning and effectiveness.Ourpointofdeparturewastherecommendedsetofguidelinesfordefiningoutcome-basedspecifications(seeChapter3).


Theguidelinesshouldnotbeseenasa‘cookbook’forallmitigationevaluations,asdecisionson, forexample,studydesign,samplingschemeorsurvey methods highly depend on the mitigation goals,targetspecies,localsituations,etc. Theguidelinescanbebetterseenasachecklistthat helps to address all relevant issues when preparingascientifically-soundplantoevaluatewhether or not the desired outcome for road mitigationhasbeenachieved.

GuidelinesHerewepresentasetoftenguidelinestohelproad planners in their assessments of whether mitigation measures are functioning in

conformance with the outcome-based specificationsprovided.

Guideline 1: Select performance indicators that are most closely related to the desired outcomeInmostcasesperformanceindicatorscanbedirectly derived from the outcome-based specifications(Box7.1).Insomecasesmultipleperformanceindicatorsmaysuit,andachoicehastobemade.Notethatifnosuitableperformanceindicatorscanbefound,theuseofanoutcome-based approach in road mitigation should be reconsidered.

Box7.1 Outcome-basedspecifications

Thepointofdepartureforanyevaluationplaninprocuring road mitigation should be the outcome-basedspecificationsprovided.Suchspecificationsshouldlinkdirectlytothegoalsofmitigation,includingadescriptionofthetargetspecies,andanswertotheSMARTapproach,i.e.,theyshouldbespecific,measurable,achievable,realisticandwithacleartimeframe.Hence,ifworkedoutwell,theoutcome-based

specificationsindicatewhatroadimpactsneedtobeaddressedandwhatneedstobeachieved,include clear thresholds for each road impact that needs to be addressed based on baseline conditions or reference standards and provide a clear time frame for both the availability of the mitigationworksandthetimeperiodoverwhichthe performance should be assessed to decide whetherthespecificationsarebeingmet.

Box7.2 RoadMitigationCalculator

Population-level effects of road mitigation may be explored with the help of models in which populationdynamicsaresimulated.Suchmodels,however,arenotwidelyavailableandoftencomplextouse.ForthisreasontheRoadMitigationCalculatorwasdeveloped(seewww.roadmitigationcalculator.eu).Thiswebtoolisnotamodelitselfbutprovidesquickaccesstomodel simulations for a few scenarios that are frequentlyencounteredinroadprojects.Thetool addresses two potential questions of road managers:(1)Howmanyanimalmovements

should be facilitated by the crossing structures toguaranteethesurvivalofthepopulation?(2)What is the survival probability of the population,giventhenumberofanimalmovements that were registered at the crossing structures?Thequestionsrelatetorespectivelythe planning of future crossing structures or the evaluationofexistingones.Currently,theRoadMitigationCalculatorcanbeusedforfiveanimalgroups:small,medium-sizedandlargemammals,toadsandsalamanders.


Guideline 2: Select a study design that incorporates the assessment of reference valuesThestudydesignshouldincludethecollectionofdataonreferencevalues,suchasbaselineconditionsorreferencestandards.Baselineconditions refer to the local conditions before mitigation.Referencestandardsmayreferto,forexample,theconditionsatreferencesites,standardsgeneratedbymodelsimulations(seeBox7.2),orstandardsthathavebeenderivedfromregulationsorpolicies.

Guideline 3: Select a study design that incorporates data collection at control sitesTheoptimalstudydesignforevaluatingroadmitigation performance includes the collection of databeforeandafterroadconstruction,attheroadsiteswheremitigationisinstalled(mitigationsites)andatroadsiteswithoutmitigation(control

sites).WerefertosuchastudydesignasBefore-After-Control-Impact(i.e.BACI)design.Collectingdata at control sites ensures that measured changescanbeattributedtothemitigation(Box7.3).

Guideline 4: Select survey methods that are the most accurate, informative and efficientThesurveymethoddependsontheselectedperformanceindicatorandtargetspecies.Ifmorethanonesurveymethodisavailable,theonethatisthemostaccurate,informativeandefficientshouldbeselected(Box7.4).Ifmultipletargetspeciesaresurveyed,surveymethodsthatmonitor multiple species simultaneously are recommended because they provide more informationforsimilareffortandcost.Consistentuse of the same methods and personnel over time is important to decrease bias and provide comparableresults.

Wildlifeoverpass‘TreekerWissel’andexclusionfencingathighwayN227intheNetherlands.


Box7.3 BACIstudydesign

In2009awildlifeoverpassandwildlifefenceswereconstructedtoreduceroad-killnumbersofroedeeratatwo-lanehighway(N227)intheNetherlands.ABACIstudydesignwasusedtoevaluate the effectiveness of the mitigation works;hence,road-killdatawascollectedbothbefore and after the mitigation at the site where the mitigation measures had been installed and

at two control sites elsewhere on the same highway.Thestudyshowedthatmitigationsignificantlyreducedtheroad-killofroedeer attheroadstretchwithfencingonbothsides.Withthehelpofthecontrolsites,aroad-killreduction of 88% could be attributed to the mitigationworks.

Box7.4 Surveytechniques

IntheNetherlandsacomparisonwasmadebetweensurveysofwildlifecrossingswith(1)theuseofonetrackbedatthecentreofanoverpassversustheuseoftwotrackbeds,oneateachentranceoftheoverpass;and(2)theuseofonetrackbedversustheuseofcameratraps.Theestimatednumberofwildlifecrossingsbasedontwotrackbeds(oneateachentrance),wassignificantlylowerifcomparedtoestimatesbasedononetrackbedinthecentreofanoverpass.Theestimatednumberofcrossings based on camera traps was significantlylowerifcomparedtoestimatesbasedonthetrackbed.Inbothcasesthe

differences in estimates increased with the decreasingbodysizeofthetargetspecies.Thereliability of the methods depends on a number offactors,someofwhichcanbemanipulatedbytheresearcher,suchasthefrequencyinwhichtrackbedsareinspectedandthetypeandnumberofcamerasinstalled.Hence,thestudydoes not conclude that one method should alwaysbepreferredovertheother,butillustrates that different survey techniques may resultinsignificantlydifferentresults,partlyduetodecisionsonhowthemethodisapplied.Rigorous comparing and testing of techniques is neededprevioustothestartofanyevaluation.

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Guideline 5: Select an appropriate spatial scale for data collectionThespatialscalefordatacollectionshouldmatchthe spatial scale of the road effect being mitigated andtheperformanceindicatorselected.Thedesiredspatialscaledependsontheroadeffect,thespeciesofconcernandthelocalsituation. A proper spatial scale can only be selected if baseline information is available on the distance over which road effects reach and the biology of thetargetspecies.Specialattentionshouldbepaidtodatacollectionatfence-ends(Box7.5).

Guideline 6: Time data collection on the basis of the mitigation goals, lifecycle of the target species and moment an effect is expectedThetimingofdatacollectionshouldbebasedprimarilyonthemitigationgoals.Forexample,iftheaimistorestoreaccesstoseasonalhabitats,the sampling can be limited to the period in which thosemigrationsoccur.Thelifecycleofthetargetspecies may affect the timing of sampling if predictable periods of presence/absence or inactivitycanbeidentified,e.g.,inthecaseofmigratoryspeciesorspeciesthathibernate.Datacollectionshouldpreferablytakeplaceforthefullperiod in which the performance indicator is relevant(Box7.6)andshouldnotbeginbeforeaneffect of the mitigation is expected to have occurred.

Guideline 7: Base study duration on the expected sampling time needed for adequate statistical powerThedurationofdatacollectionshouldallowforsufficientstatisticalpowertodeterminewhetherornotthemitigationresultsinasignificantchangeintheperformanceindicatorofconcern.Consequently,studydurationiscloselyrelatedtothe chosen performance indicator and the characteristicsofthestudiedspecies.Italsorelates to the number of data points that are expectedtobecollectedineachyearorsample.However,evenifyearlydatasetsarerelativelylarge,itmaybeadvisabletocollectdataformultiple years as some performance indicators mayvaryconsiderablyacrossyears.

Guideline 8: Use a sampling frequency that allows for rigorous estimates of the performance indicatorThefrequencyofsamplingshouldallowforrigorousestimatesoftheperformanceindicator.Forexample,inmostcasessurveyingroad-killjustonceamonthwillnotbesufficienttocalculaterigorousestimatesofmeanroad-killperyear.Andestimates on between-population movements will likelybemoreaccurateif,forexample,trackbedsaresampleddailyinsteadofonceaweek.Pilotstudies may be needed to assess the optimal sampling frequency in which sampling effort is

Box7.5 Fenceends

Positive effects at a mitigation site may be nullifiedbynegativeeffectsinadjacentareas,forexampleasaresultoffenceendeffects.AthighwayN227intheNetherlandsroad-killwasnot only monitored where fences were installed but also at the road stretches beyond the fences.Atthesefenceendsites,anoppositetrendinroad-killnumberswasfound;aftermitigation,atonesiteroad-killnumberswentdown,whileattheothersiteroad-killnumberswentup.Althoughthechangesinroad-killnumberswerenotstatisticallysignificant,

possiblyduetothelimitedsamplesize,thedataclearlyillustratethatroad-killnumbersbeyondthe fence ends may change after road mitigation measureshavebeentaken.Italsoshowsthatthe direction of change may differ per fence end site.Hence,fenceendsitesshouldbeincludedin all road mitigation evaluations where fencing is included to avoid that the effects of mitigation areover-orunderestimated.AthighwayN227,asignificant88%road-killreductionchangesintoastatisticallynotsignificant50%iffenceendeffectsaretakenintoaccount.


minimisedwithoutjeopardisingaccuracy.

Guideline 9: Measure explanatory variables that may affect mitigation performanceVariables other than the performance indicators of interest should also be measured to improve the interpretationoftheresults.Especiallyifdatacollectionatcontrolsitesislacking,measuringexplanatory variables will allow for stronger inferences concerning the causes of observed differences.Werecommenddocumentingspatialand/ortemporalvariabilityin:(i)featuresoftheroadandtraffic;(ii)featuresoftheroadmitigationworks;(iii)featuresofthesurroundinglandscape;and(iv)weatherconditions.

Guideline 10: Make the evaluation report and raw data widely availableInordertolearnfromeachotherandmakesurethatallfindingscanbeeasilyaccessedandused,new methods to report and share the data should bedeveloped.Werecommenddevelopingastandard protocol for archiving the collected data acrossprojects,includingallrelevantmeta-data.Furthermore,itisessentialtoarrangepeerreviews of reports and aim for publication in scientificjournalstoimprovethequalityandrigorofthescientificmethodsaswellasimproveaccesstothefindings.Thiswillhelptoensurethatfutureroad mitigation projects can build on existing knowledge.

Box7.6 Timingofdatacollection

AstudyonfivewildlifeoverpassesintheNetherlandsshowedthatthereislowprobabilityof detecting all species in scenarios where surveysareconductedonlyinspringorautumn,evenifthesurveyscoverthewholeseason.Detection probabilities are higher if the surveys takeplaceinbothspringandautumn;however,foracompletespecieslist,surveysmusttakeplaceforatleasttwelveweeksinbothseasons.Onaverage,ittakes240surveydaystodetect

allspecies.Thisnumberofsurveydayscanbeloweredifthestartingdateisinspring,especiallyinMarch.Yearlycrossingratesareeither overestimated or underestimated if surveyperiodsarelimited;however,thevariationbetweenspeciesishigh.Consequently,we conclude that great care is required if one is planningonlimitingsurveystocertainweeksormonthsoftheyear.

Relativedifferenceinnumberofspeciesdetected(left)andyearlycrossingrateestimatesofallspecies(right),depend-ingontheseasoninwhichthesurveytakesplaceandnumberofsurveyweeksperseason.

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Implementingtheguidelines• Successful evaluations of road mitigation

performance will require close collaboration - from the earliest stages of a road mitigation project - between research ecologists and those whoplan,design,constructandmanagetheroad.Werecommendresearchecologistsinroadagencies to become more involved in the procurementprocessofroadmitigationworks,e.g.,towriteSMARToutcome-basedspecifica-tions,organisethecollectionofbaselineinfor-mation and judge evaluation plans proposed by contractors.Theresearchersneedtoinformtheroad agency of the essential components of good study design for road mitigation evalua-tions.

• We recommend contracting an independent contractor to evaluate road mitigation perfor-mance.Itisnotadvisabletoputboththedesigning/constructing and evaluating the

mitigationmeasures–whetherornottheobjectivesarebeingmet-inonecontract.Besidespossibleconflictsofinterests,thisapproach allows for selecting a contractor for the evaluations solely based on their ecological knowledgeandexperience.

• We recommend forming an independent advi-soryboard,consistingofexperiencedroadecologists,toassisttheroadagencyinpreparingoutcome-basedspecificationsaswellasinplanning and conducting evaluations that meet goodscience.Suchanadvisoryboardmayalsoplayakeyroleinensuringthatacquiredknowl-edge and best-practices will be available to all stakeholders.

• We recommend that the preparation of an evaluation plan for planned road mitigation measures is made an inseparable part of the legal processes that must be followed during the roadplanningandprocurementstages.Evalua-

Roedeerbuckcrossingatrackbedatawildlifeoverpass.


tions of mitigation performance should not be optional but rather a statutory duty that forms an integrated whole with the procurement of the works.

• We recommend developing a strategy for systematic assessments of baseline conditions andreferencestandards.Baselineconditionsshouldbeknownatthestartofprocurement,and this also applies to certain reference stand-ards that the road agency may want to pre-scribe.Thisimpliesthatanewwayofworkingshould be adopted as currently such systematic assessmentsareoftenlackingatthestartofprocurement.

• We recommend that all necessary resources to evaluate road mitigation performance are securedbeforehand.Roadmitigationevaluationsbasedonoutcome-basedspecificationsrequiresignificantlymoreresourcesthanevaluationsbasedondesignspecifications.Therefore,earlyinsight into the costs of evaluation studies is required,andthesecostshavetobetreatedasan integral part of the road or road mitigation constructionproject.

• We recommend that the outcome of all evalua-tions,includingresearchreportsandrawdata,ismadeavailabletoallstakeholdersthroughanopenaccessdatabase.Researchmethods,results and conclusions should be documented systematically,thusallowingforquickreferenceandpropercomparisonsbetweenprojects.Furthermore,alldatashouldbeanalysedandreported in a timely manner to ensure existing structurescanbemodifiedwithinanadaptiveframeworkandthedesignoffuturemitigationmeasurescanbeimproved.

Anevaluationofmitigationworksbasedontheguidelines presented here will clearly require more efforts and resources than most current approaches.Ontheotherhand,itwillprovidemuchmorefeedbackonwhatwedorightandwrongandisstronglylinkedtothereasonsofwhythemitigationwasimplemented,i.e.,themitigationgoals.If,inturn,thesegoalsarestronglylinkedto(inter)nationallegalandpolicyplans,theoutcomeoftheevaluationswillresultinabetterviewonhowthemitigationworks

contribute to overall strategies for biodiversity conservation.Thiswillevenbemoresoifevaluation reports are standardised and the results as well as raw data - from both studies that showed successes and studies that exposed failures-arestoredinanopen-accessdatabase.Thiswillenableallstakeholderstoreviewtheinformation,betterfacilitatelearningfromprevious projects and allow for more comprehensive meta-analyses of the collected data.

Source: This chapter is a summary of SAFEROAD deliverable 6, 13 and 15.


Chapter 8

What is next?TheSAFEROADprojecthasaddressednewdevelopmentsinlegislation,policyandprocurement;thecost-efficiencyofdifferentmitigationstrategies;maintenancepracticesthataimatreducingroad-wildlifeconflicts;theeffectivenessofmitigationmeasurestomaintainviablewildlifepopulationsandimprovetrafficsafety;andmonitoringapproachestoassesswhetherroadmitigationgoalshavebeenachieved.Theprojectprovidesguidelinestopractitionersinvolvedinroadplanning,constructionandmaintenancefortheimplementationofresearchfindingsindailypractice.However,whatisneededtoencouragetheuseofproject outcomes and the improvement of mitigation practices? What should our next steps betomakesuretheSAFEROADprojecthasanimpact?

Noappliedresearchmattersifitdoesnotreachthepeopleandinstitutionsitwasmeantfor. ThatiswhyweconsiderourdeliverablesintheSAFEROAD project not as an ‘endpoint’ but as a‘startingpoint’.Ournextstepswillallfocus oncommunicatingtheprojectfindingstopolicymakers,roadplanners,roadmanagers,researchers,consultantsand,tosomeextent, thegeneralpublic.Thisambitionhasalready beenputintoactionassomeresearchfindingshaverecentlybeenpresentedat(inter)nationalconferences and seminars where both scientists andpractitionersconvene,suchasIENE2014,ICCB2015,ICOET2015andIENE2016.Wewillagain use these forums in the near future to disseminate,discussandbuildupontheprojectoutcomes.

Withintheproject,seventechnicalreportsbut alsosixscientificpapershavebeendrafted. Thesepaperswillbesubmittedtopeer-reviewedjournals.Notonlywillthisensurethattheresearchispresentedtothescientificsociety,butitwillalsofunctionasascientificqualitycontrolandthusprovidescientificsupporttotheproposedguidelines.

TheSAFEROADprojectwasoneofthreeinthe

CEDRTransnationalRoadResearchProgrammeCall2013:RoadsandWildlife.Togetherwiththeothertwoprojects-HARMONYandSafeBatPaths- SAFEROAD will be used to compile a new handbookforpractitioners.ThisCEDR European Handbook for Wildlifewillpresentallkeyfindingsand provide guidance for their implementation in thedailypracticeofroadplanning,constructionandmaintenance.ThehandbookwillnotreplacetheCOST341-handbookonWildlife and Traffic,publishedin2003,butwillcomplementitasthenewhandbookwilladdressissuesthatwerenotincludedoronlybrieflytouchedonbefore.Hence,thenewhandbookwillenlargeour‘toolbox’todealwith the challenge of avoiding road-wildlife conflicts.

Successfullyimplementingtheresearchfindings ismainlyinthehandsoftheroadauthorities.Modificationsinroadplanning,designingandoperatingprocedures,apossibleshifttowardsoutcome-basedspecificationsinprocurement,moreemphasisondefiningmitigationgoalsandan adapted approach to evaluate mitigation performancedemandanewmindset,differentskillsandexpertiseandamoretransdisciplinarywayofworking.Theyalsopossiblyrequireorganisational changes that allow engineers and


environmentalexpertstoworkinclosercollaboration as well as new regulations on changes in procedures and the division of responsibilities.Adifferenttimeplanningin road projects may even be required as proper evaluations of road mitigation performance need to start long before the measures have been installed.Andstaffmayhavetobetrainedtobetterpreparethemfornewtasksandincreasetheir understanding of the ecological context in whichthesetaskshavebeendeveloped.

Finally,furthereffortsareneededinstrengtheningthecooperationbetweenallstakeholdersinvolvedinsolvingroad-wildlifeconflictsacrossEuropeandbeyond.Itisvitaltoexchangenewknowledgeandbest-practicesinordertoavoidrepeatingmistakes

and increase the effectiveness of our mitigation actions.Cooperationisalsoessentialtoaddressnewchallenges,suchasclimatechange.Onlythencanwehaveachanceofcreatingaroadnetworkthatissafeforbothwildlifeandpeople.

Ontheroadagain.....Closecollaborationisneededbetweenallinvolvedstakeholderstomakeroadssafeforbothwildlifeandpeople.


SAFEROAD Deliverables

Technicalreports:1 Technicalreport1-Roads and wildlife: Legal

requirements and policy targets (Helldinetal.2016)

2 Technicalreport2-Guidelines for outcome-based specifications in road mitigation(VanderGrift&Seiler2016)

3 Technicalreport3-Modelling the performance of road mitigation strategies: Population effects of permeability for wildlife(Seileretal.2016)

4 Technicalreport4-Cost-efficacy analysis: wildlife and traffic safety(Seileretal.2016)

5 Technicalreport5-Road maintenance guide-lines to improve wildlife conservation and traffic safety(Roselletal.2016)

6 Technicalreport6-Guidelines for evaluating the performance of road mitigation measures (VanderGriftetal.2016)

7 Technicalreport7-Case studies on the effect of local road and verge features on ungulate-vehicle collisions(Seileretal.2016)

All deliverables are available through www.saferoad-cedr.org

Scientificpapers:8 Van der Grift et al. - Effectiveness of road miti-

gation for wildlife: A review9 Rytwinsky et al.-Howeffectiveisroad

mitigationatreducingroad-kill?Ameta-analy-sis

10 Ottburg & Van der Grift - Effectiveness of road mitigationmeasuresforacommontoad(Bufo bufo)populationintheNetherlands

11 Rolandsen et al.-Youshallpass!Amechanis-tic evaluation of mitigation efforts in road ecology

12 Seiler et al. - Effects of roads on wildlife population viability

13 Van der Grift et al. - Estimating crossing rates at wildlife crossing structures: methods matter!

Other:14 Movie:Tunnelsfortoads15 Road Mitigation Calculator (www.roadmitigationcalculator.eu)


Colophon

AuthorsEdgarvanderGriftAndreas Seiler

Carme RosellVanya Simeonova

SAFEROADProjectTeam

www.wur.nl

EdgarA.vanderGriftVanya SimeonovaPeter SchippersArjandeJong

MirjamBroekmeyerFredKistenkasFabrice Ottburg

www.slu.se

Andreas SeilerGuillaumeChapronJulianKleinMattias Olsson

www.minuartia.com

Carme RosellRoser Campeny VallsFerranNavàsAlbert Cama

Marc Fernández

www.calluna.se

Jan-OlofHelldinKristinaKvamme

www.conservation.uni-kiel.de

HeinrichReck

www.rodis.ie

EugeneOBrien

www.nina.no

Christer Moe RolandsenErlingJ.Solberg


CEDRProgrammeExecutiveBoardLarsNilsson/AndersSjölund(Projectmanager)ElkeHahnOla-mattis DragesetAdamHoflandMarianneLundUjváriVincentO'MalleyTonySangwineUdoTegethof

MoreonCEDR:www.cedr.eu

FundingTheresearchpresentedinthisreportwascarriedoutaspartof theCEDRTransnationalRoadResearchProgrammeCall2013:RoadsandWildlife.ThefundingfortheresearchwasprovidedbythenationalroadadministrationsofAustria,Denmark,Germany,Ireland,Norway,Sweden,NetherlandsandUK.

TobecitedasVanderGrift,E.A.,A.Seiler,C.Rosell&V.Simeonova.2017.Saferoadsforwildlifeandpeople.SAFEROADFinalReport.CEDRTransnationalRoadResearchProgrammeCall2013:RoadsandWildlife.CEDR,Brussels.

Photo creditsRijkswaterstaat coverGLFMedia insidecoverEdgarvanderGrift page2,12(top),16,19,23,41,45Jan-OlofHelldin page5FabriceOttburg page12(bottom),21NiklasLuks page13(top)AndreasSeiler page13(bottom),25JamieHall page14 Ole Roer page 22MattiasOlsson page27,29GeneralitatdeCatalunya page35Carme Rosell page 36BjörnSchulz page38TobbeLektell page48SkywardKickProductions page 52

Wageningen,December2017

Partners

SaferoadofficeWageningenUniversity&ResearchEnvironmental ResearchDroevendaalsesteeg 3 Building1016708PBWageningenT+31317481600

Project [email protected]

Contact personVanya [email protected]

www.saferoad-cedr.org

Documents

Final report of the SAFEROAD project · 2018. 6. 19. · Final report of the SAFEROAD project | 2 Animals that cross the road may result in an unforgettable experience but more often