Impact of winter changes

IMPACTS OF CHANGES IN WINTER SEVERITYON WINTER MAINTENANCE Technical Committee B.5 – Winter Service

www.piarc.org2013R13EN

The World Road Association (PIARC) is a nonprofit organisation established in 1909 to improve international co-operation and to foster progress in the field of roads and road transport.

The study that is the subject of this report was defined in the PIARC Strategic Plan 2007 – 2011 approved by the Council of the World Road Association, whose members are representatives of the member national governments. The members of the Technical Committee responsible for this report were nominated by the member national governments for their special competences.

Any opinions, findings, conclusions and recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of their parent organizations or agencies.

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International Standard Book Number 978-2-84060-330-6

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STATEMENTS

IDENTIFY IMPACTS OF CHANGES IN WINTER SEVERITY ON WINTER MAINTENANCE…2

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This report has been prepared by a working group of the Technical Committee B.5 Winter maintenance of the World Road Association (PIARC).

The contributors to the preparation of this report are:

• Gudrun Öberg (Sweden),• Odile Coudert (France),• Mario Marchetti (France),• Miguel Tremblay (Canada),• Didier Giloppé (France),• Hara Fumihiro Hara (Japan),• Daniel Huang (Canada),• George Christoglou (Greece),• Georgios Barbas (Greece),• André Pans (Belgium),• Gojmir Cerne (Slovenia),• Jae-Hyeong Kim (South Korea),• Vidar Engmo (Norway).

The editors of this report are:

• Rick Nelson for the English version,• Didier Giloppé for the French version.

The translation into French of the original version was produced by Didier Giloppé, Guillaume Derombise and Mario Marchetti (France).

The Technical Committee was chaired by Gudun Öberg (Sweden). Didier Giloppé (France) and Paul Pisano (USA) were respectively the French and English-speaking secretaries.

The French version of this report is referenced 2013R13FR. ISBN : 978-2-84060-331-3


2013R13EN SOMMAIRE

SUMMARY ..................................................................................................................................................5

INTRODUCTION .......................................................................................................................................6

1. CLIMATE CHANGE - GENERAL CONSIDERATIONS ................................................................6

1.1. OBSERVATIONS IN COUNTRIES AROUND THE WORLD .....................................................61.2. FORECASTS (DAYS OF SNOW, SNOW COVER) ....................................................................111.3. EXPECTED IMPACTS ON WINTER MAINTENANCE ...........................................................15

2. IMPACTS ON WINTER MAINTENANCE .....................................................................................17

2.1. LITERATURE REVIEW ...............................................................................................................172.2. IMPACTS ON DE-ICERS CONSUMPTION AND USE .............................................................262.3. IMPACTS ON MANPOWER .......................................................................................................272.4. IMPACTS ON COSTS ..................................................................................................................282.5. SPECIFIC CASE OF URBAN AREAS, REMOTE AREAS ........................................................28

3. IMPACTS ON INFRASTRUCTURES ..............................................................................................30

3.1. CHANGES IN TEMPERATURE ..................................................................................................303.2. FROST/THAW CYCLES. FROST DIMENSIONING .................................................................303.3. CONSTRUCTION AND CLIMATE CHANGES. OTHER ASPECTS ........................................33

3.3.1. Longer construction season. Materials characteristics .......................................................33

4. CONCLUSIONS ....................................................................................................................................36

5. BIBLIOGRAPHY / REFERENCES ..................................................................................................37


2013R13EN SUMMARY

Data from the past years indicate a significant evolution and change in temperature profiles, precipitation, and generally deviation from traditional seasonal cycles. Snow events became more intense and sudden, and forecasts are getting more difficult. Based on Intergovernmental Panel on Climate Change (IPCC) scenarios, some significant changes can be identified, specifically for winter months.

Impacts on infrastructure are analysed through some examples such as de-icer consumption, manpower, and costs. A specific part describes infrastructure impacts, specifically on frost/thaw cycles.

De-icer consumption continues to increase despite mild winters. There is no clear consistency with winter severity. Budget constraints and cuts might cause drastic change in de-icer use. Experienced staff is now near retirement and institutional knowledge will leave with them. Mild winters provide the opportunity to set requirements less strict than they were, leading to a substantial saving. The purchase and renewal of winter equipment seems to be conducted with a strategy based on modularity and optimisation to avoid a use solely dedicated to winter maintenance, except for some specific cases such as airports. Winter maintenance is relatively well defined within the urban and wide area networks, however, the advancement is not quite as well developed for isolated networks.

Based on IPCC projections, the question of frost susceptibility might no longer be an issue in some regions currently experiencing severe winters.


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INTRODUCTION

Over the past years, data shows the evolution and change in temperature profiles, precipitation, and more variation in seasonal cycles. Snow events become more intense, sudden, and difficult to forecast. In addition, a significant increase in traffic volumes was observed over the past decade, along with an increase in road user expectations.

More considerations are now given to the environmental impacts of human. This report is focused on winter maintenance because of weather variability and its practices; particularly the use of trucks and chemical de-icers. Concerns have been raised over the use of de-iceing chemicals, and the policies of winter maintenance or infrastructure constructions rules. Nevertheless, climate change identified in this work is mainly associated with a progressive disappearance of winters.

This report first provides some general considerations about climate change around the world with some focus over a few countries. This part will mainly deal with observations and specifically with forecasts of snow cover. A short literature review presents what are the expected impacts on winter maintenance of this climate change. This aspect is detailed in a second part. De-icer consumption, manpower, and costs will be described. A third part will be dedicated to infrastructure impacts, specifically on frost/thaw cycles. 1. CLIMATE CHANGE - GENERAL CONSIDERATIONS

1.1. OBSERVATIONS IN COUNTRIES AROUND THE WORLD

Climate change is mostly associated with the image of disappearing winters, and warmer global temperature. In the case of western European countries over the latest winters, the occurrence of some particularly hard winters in specific regions causing massive travel inconvenience, the question of climate change is raised, again and again, along with the economic impact on winter maintenance.

To provide the beginning of an answer to this situation, weather services have identified 30 regions and gave, for each parameter of each region, the climate projections and the associated uncertainties, according to the A and B scenario shown in figure 1, next page.

The differences between the two scenarios are larger in terms of precipitation. Broadly, the models provide an increase in precipitation in the far North and a decrease in the far South. The line between growth and decline differs between both scenarios and seasons. During the winter months the simulations give more


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precipitation in large parts of Europe including Scandinavia. As shown in figure 1, however, there are quite large regional differences between the two, particularly for elements of Norway’s Atlantic coast and the western parts of Iceland. In these areas, there are almost no changes, or even a small decrease in one scenario while in the second scenario one sees a large increase in precipitation along the Atlantic coast of Norway. These differences depend on how the global models simulate the large-scale flow in the area. The example shows the importance of the mass flow for the regional climate in an area. During the summer, all scenarios give a reduction of rainfall in the southern part of Scandinavia.

FIGURE 1 - CALCULATED CHANGE OF PRECIPITATION FOR WINTER MONTH (A) THE BIGGEST CHANGES AND (B) THE SMALLEST CHANGES

ACCORDING TO ROSSBY CENTRES SCENARIOS

Let us consider the French situation when it comes to observed weather data and projections as summarized in table 1, next page.

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TABLE 1 - OBSERVED CLIMATE CHANGE IN FRANCE

Temperatures

• Average temperature Tm : increase of 1°C over the 20th century

• Increase of TN (around 0,9°C to 1,5°C) greater than TX (around 0,1°C to 1,1°C)

• East France to West France warming gradient of average minimum temperature TN

• North to South warming gradient of average maximum temperature TX.

• Maximum warming of TN in summer• Maximum warming of TX in autumn• All the indicators related to temperatures turned to warming :

decrease of frost days, more frequent heat waves….

Precipitations

• Increase around 10% over the 20th century• More observed increases in the North than in the South• Quite global increases in winter• Summer : decreasing precipitations and more intense drought• No trend on intense precipitation events

Sunshine duration

• Decrease of approximately 0,3% of the annual amount every 10 years

• South to North decrease gradient• More intense decreases during spring.

Wind • No increase of storms since 1950.

Figure 2 presents the observed trends for precipitations and minimum temperatures in winter in France :

FIGURE 2 - EXAMPLES OF TRENDS IN FRANCE FOR THE 1901-2000 PERIOD

Trend of winter precipitations (the arrow orientation and color intensity

give the trend) (1901-2000)

Trend of average minimum temperature in winter (from red (high) to pink (low))

(1901-2000)


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In Hokkaido (Japan), in most years since 1990, the annual temperature average has been above normal, and it has risen by about 0.8°C over the past 100 years.

Figure 3 shows the differences between annual winter temperature averages and normal temperature during the winter from 1890 to 2010. The winter average temperature is the mean value of the monthly temperature averages during the winter months from December to March. The normal winter temperature is the mean of the annual winter temperature average for 30 years from 1971 to 2000 in these places. The differences between annual winter temperature averages and normal value are greater than those between the annual temperature averages and normal. The annual winter temperature average increased by about 2.1°C for the past 100 years.

FIGURE 3 - CHANGES IN THE DIFFERENCE BETWEEN THE ANNUAL WINTER TEMPERATURE AVERAGES AND NORMAL TEMPERATURE IN HOKKAIDO

Significant long-term fluctuations in annual cumulative snowfall have not been seen except in lightly snowy areas where the last five years tends to be significantly increasing.

Annual heavy snowfall frequencies in Hokkaido were examined. A day of heavy snowfall is defined as a day that records 30 mm or more precipitations within 24 hours, and zero or lower day average temperature, The days with heavy snowfalls during the winter (Dec.-Feb.) from 1961 to 2001 were selected for the analysis.

As shown in figure 4, next page, the heavy snowfall frequencies have tended to increase since 1980. The heavy snowfall frequencies have become two to three times more in recent 10 years, compared with those in years before 1980. This trend is


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significant in areas that were once previously lightly snowy areas. Recent climate changes in Hokkaido can be summarized from the analysis results of the climatic data above. First, annual average temperatures in Hokkaido tend to be increasing. Particularly, the increase in the annual average lowest temperatures is significant as represented by the increase in annual winter temperature averages and the frequency of heavy snowfalls tends to be increasing. Particularly, unprecedented heavy snowfalls are beeing seen in previously lightly snowy areas, though annual cumulative snowfalls have not been greatly changed in snowy areas.

FIGURE 4 - INCREASING HEAVY SNOWFALL FREQUENCIES

The annual heavy snowfall frequency trends to be increasing since around 1980. in recent 10 years, the frequency comes to be two to three times more than those in years before 1980.


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1.2. FORECASTS (DAYS OF SNOW, SNOW COVER)

The resources allocated to winter maintenance are greatly dependant on the winter severity. Allocations of resources can, therefore, be made based on long term climatology and short term events:

• a based level of resources can be allocated in accordance with the climatology of the region, its characteristics, and the nature of winter events. For this portion, an indicator could be created as a function of the number of snow occurrences, black ice events, and so on. This would address the designed buildings, materials, equipment, and financial resources for winter maintenance;

• a second part is directly linked to field operations, and depends on road weather events experienced from a statistical point of view. This part could be described by a normalized winter maintenance index (called IVH100) calculated from meteorological parameters such as severity of the winter and the corresponding maintenance.

There are different scenarios for the change in future temperature. Regarding the two stastical parameters, the average and the variance, the change in temperature could come from:

• an increase of the average; meaning higher temperatures and more heat waves,• an increase in the variance; meaning more higher and lower temperatures, and

more heat and cold waves,• an increase of both the average and the variance.

In each case, the consequences, meaning higher temperatures and more heat waves, and very little changes regarding cold temperatures.

Data from weather services have been compiled over a large area to obtain a map representing the “sensitivity” of a country or region to snowfall. Based on a IPCC scenario, it is possible to evaluate how this sensitivity will evolve. An illustration is given in the case of France in figure 5, next page.


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FIGURE 5 - NUMBER OF DAILY SNOW OCCURRENCECURRENT SITUATION (1996-2006) (A) AND FUTURE (2070-2100) (B)

TABLE 2 - FRENCH PROJECTIONS FOR THE 21TH CENTURY

Temperatures

• Increase of temperatures• Higher warming in summer than in winter• In summer: higher warming in the South of Europe than in the

North (48N)• In winter: higher warming in the East part of Europe than in the

West part.

Events related to temperatures:

• more frequent heat waves: very likely• more warm summer days: likely• fewer frost days: very likely• fewer cold days: likely • fewer cold extremes events in winter: very likely in the North

of Europe, likely in the South• reduced diurnal temperature range: likely

Precipitations

• More depressions and precipitations in the North of Europe• Fewer depressions and precipitations in the South of Europe

The position of the limit between less and more precipitations in Europe is uncertain.

Events related to precipitations:

• more intense precipitation: very likely• more intense precipitation events: likely in the center of Europe,

uncertain in summer in Europe and Mediterranean sea.• more regions affected by drought in summer: likely.


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FIGURE 6 - A GLOBAL INCREASE OF TEMPERATURE (2 m ABOVE SURFACE) FOR WINTER MONTHS (A AND B) ,

AND PROJECTIONS FOR AVERAGE ANNUAL TEMPERATURE (C) AND MINIMUM WINTER TEMPERATURE (D) (YEAR 2030, IPCC A2 SCENARIO)

Based on the projections of the IPCC A2 scenario, a global increase of temperature is to be expected, with a higher warming in Eastern Europe than in the Western part.

The difference between the two maps is noticeable, particularly in the north-east part of France which is one of the most sensitive areas of the country with respect to winter. These observations can be explained by the fact that, even if precipitation during the winter will increase in the future, as temperatures increase (an increase of about 3°C in average between both periods has been shown in the calculation of future frost indexes) the number of snow events will decrease.

The same approach could be developed with the number of consecutive days of snow, an interesting indicator of winter maintenance difficulty. Figure 7, next page shows the maximum number of consecutive days of snow in the current period, based on


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measurements from meteorological stations and in the future situation. The maximal number of consecutive snow day events will be about 6 in the future, while values are currently greater than 10 in the North East. The situation of the North-East of France in the future scenario will be equivalent to the current one in the South-West.

FIGURE 7 - NUMBER OF DAILY SNOW OCCURRENCES IN FRANCE CURRENT SITUATION (1996-2006) (A) AND FUTURE (2070-2100) (B)

One additional indicator on winter maintenance difficulty is the snowfall intensity. In the case of France, an assessment of the evolution of the intensity parameter or more exactly snow height fallen during 24 hours, was performed. A comparison was then done between the current and the future situations, the intensity being organized in different classes. A global decrease could be noticed in the intensity based on this trend (figure 8).

FIGURE 8 - AVERAGE NUMBER OF SNOW OCCURRENCE IN ACCORDANCE WITH INTENSITY CLASSES IN FRANCE


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1.3. EXPECTED IMPACTS ON WINTER MAINTENANCE

Based on the available data presented in the previous paragraphs, two kinds of impacts can be expected, one in the sort term, and another in the long term.

On the short term, the main difficulty is economical. Most winter budgets are built on the basis of the previous winter events. Considering winters situations are fluctuating a lot from one winter to the very next, it raises many difficulties. One aspect is when winter maintenance is conducted by contractors, then the nature of the contract has to be prepared to obtain the best service. What is the most appropriate contract: one based on a global amount, or number a winter operations? A similar issue is met in the management of de-icers. The drastic changes occurring during one winter makes the management of de-icer stock difficult, from the order of the material to its storage conditions. Indeed, how many tons of de-icers should be ordered, would the suppliers be able to provide de-icers in case of a late order, or in case of emergency, and are there means to make a sustainable storage of de-icer to avoid dissemination into the environment? Such aspects are highly linked to local winter infrastructure behaviour, since climate changes has also local consequences.

A calculation is going on of the salt consumption for different years during the 21st century, and built on climate change scenario. This will be presented for different weather/road conditions (ice or snow) and for some different regions in Sweden. The same rules for anti-icing or de-icing during the different years as now.

In the long term, the climate change raised many questions too:

• How should winter tools be managed in terms of investments, should services keep on purchasing dedicated vehicles, or look for a global modularity, with vehicles equipped with winter maintenance tools during the winter season, and used for other purposes the rest of the year?

• In the field of decision making, what about investments on tools such as Vinterman, or other platforms designed to collect and to aggregate winter data?

• Are there still relevant, or should efforts be made to adapt tools to extreme, and sudden events?

• The coming years are the ones of massive retirements, and therefore the progressive loss of experience in winter maintenance. Considering this fact and the difficulty to get a good knowledge on climate change, what is the most suitable position with respect to the training of winter staff?

In Japan, there were 2,081 road closures on national highways during the 1995 to 2004 period in Hokkaido. Among them, road closures resulting from snowfall account for more than a half (57%) of all road closures. Snowstorm takes 39% of the causes of snow oriented road closures. Climate change effects on winter road


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maintenance in Hokkaido are shown in figure 9. The identified effects of climate change include 1) average temperature rises and 2) locally intensive heavy snowfalls or snow storms.

FIGURE 9 - EFFECTS OF CLIMATE CHANGE ON WINTER ROAD MAINTENANCE

There are two winter road maintenance issues that may arise relating to the temperature rise.

First, the temperature rise may frequently cause the emergence of icy road surfaces in northern Hokkaido or on mountain passes where the differences of daytime and nighttime temperatures are great. The temperature rise have led to daytime temperature increase high enough to melt snow on road surfaces and the melt snow is frozen at night. Repeated snow melting and freezing results in the emergence of icy road surfaces. To prevent skidding accidents on such icy roads, types of anti-freezing agents and agent spreading methods need to be reviewed.

Second, the temperature rise turns dry snow into wet one, and it is likely to trigger avalanches on slopes where avalanches have been unlikely to occur, or slush avalanches. There are examples where avalanches pass through avalanche control fences and reached the roadway blocked traffic.

Intense snowfall may result in snow cover even on steep slopes that has previously been with little snow, which is likely to be led to avalanches which sometimes may flow over roadways and block traffic.

Climate change may cause heavy snowfalls or extensive snowstorms more frequently than before.

Temperature rise

Heavy snowfall or snowstorm increase in usually lightly snowy areas

• Frequent emergence of icy road surfaces caused by temperature difference between daytime and nighttime.

• A wide range of traffic troubles caused by an unusual scale of heavy snowfall beyond the conventional capacity of snow removal systems. (Extensive and long-time road closures).

• Occurence of a large-scale avalanche from extreme snowfall. Such an avalanche scale exceeds controllability of existing roadside avalanche facilities.

• Occurence of unusual types of avalanches (wet snow surface slab avalanche) due to heavy snowfall or wet snow from temperature increase.


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Such phenomena have been typically seen in east Hokkaido that used to be a lightly snowy area. The greatest record, 171 cm snowfall during the period was seen in Kitami.

Figure 10 shows vehicles stuck in snow because of the snowstorm in Sweden. The extensive and serious traffic troubles continued long enough to badly affect local communities.

FIGURE 10 - A WET SNOWFALL CAUSED HEAVY VEHICLES BLOCKING UPHILLS AND LONG QUEUES ON E18 IN SWEDEN

Besides the technical aspects with a reduction of service, the social acceptance of this situation has to be prepared.

2. IMPACTS ON WINTER MAINTENANCE

2.1. LITERATURE REVIEW

The search of references was conducted on the web and through publications at the latest PIARC and SIRWEC congress.

Many publications and studies deal with climate change. Nevertheless, as the field is restricted to one specific area, the number of documents become scarce. Documents are mainly giving general information, and very few provide details on climate


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change impacts on transportation in general. Very few studies are dedicated to the impact of climate change on winter maintenance. An analysis and a summary of this literature, along with some comments is given thereafter.

Lee Chapman, University of Birmingham, UK Anna Andersson, Goteborg University, Sweden Climate change and winter road maintenance: Will complacency be the new killer? [48]

Winter weather can be a significant cause of road traffic accidents. This paper uses UKCIP climate change scenarios and a temporal analogue to investigate the relationship between temperature and severe road accidents in the West Midlands, UK. This approach also allows quantification of the changes in the severity of the winter season over the next century in the region. It is demonstrated that the predicted reduction in the number of frost days should in turn reduce the number of road accidents caused due to slipperiness by approximately 50%. However, the paper concludes by warning against complacency in winter maintenance regimes. A warmer climate may result in budget cuts for highway maintenance which in turn may well reverse long term declining accident trends.Based on an evolution scenario (202, 2050, 2080), an accidentology evolution due to snow or ice on pavements is deduced. Traffic evolution is also taken into account. The number of frost days will go down, and so do the amount of de-icers and accidents. Many references on accidents during wintertime.

Gudrun Öberg, VTI, Lennart Lindbom, Swedish Road Administration, NRA (Nordic Road Association). Climate Change in Nordic Countries – influence on roads– adaptation of road administrations. Unpublished report from 2008-03-25 http://www.vegagerdin.is/nvf41.nsfseeprosjekterklimaforandringar (in Nordic languages). 64 pages. Summary in English Climate Change – Influence on Roads – Adaptation of Road Administrations. 9 pages. [17]

A working group of the Nordic Road Association “Maintenance and operation”, has had the task to study the climate change and what will be important in the future according to maintenance and operation. The working group had participants from road administrations, meteorological and research institutes. A method was used, as a first step, to find out in what areas it is most important to start acting depending on climate change. The method of risk calculation is a method used by the Swedish Road Administration (SRA) in administrative projects but also to make risk analysis of damages of roads. The risk analysis has been made for Denmark, Finland, Faroe Islands, Iceland, Norway and Sweden. The analysis is made in two steps. First we have to decide what the probability is that something happens on collected national level. It can be some big events or gradual changes. The probability is estimated as if no preventive measures are taken other than the usual today.The second step is the consequence and with that means the estimated cost for the event for the road administration, road user and society at large. Out of these countries Norway will have the largest influence of the climate change. This is very much depending of that Norway is a mountainous country and also has a long coast compared to the size of the country. This is also true for Faroe Islands but there the climate will not change as much as in Norway.Risk analysis based on one identified scenario. Definitions of the most important actions to conduct. Broad analysis where winter maintenance is poorly considered. Interesting for the methods and immediate commitments.


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Chris Plumb, Highways Agency UK, The effects of Predicted Climate Change on Winter Service Operations [49]

The Highways Agency Climate Change Adaptation Strategy (2008) stresses the need for measured and timely strategies to allow all of their operations to evolve in synchronisation with a changing climate without contributing to its cause. The Agency’s Winter Service operations are greatly influenced by climate and will be affected by future changes. This report considers the projected trends in climate change and the effects they are likely to have on Winter Service operations.Interesting method, with the description of an operational approach, extended bibliography

Caroline Walters, The effect of Climate Change on 3CAP’s Highway Network Policies and Standards [50]

This report forms the concluding task (Task 5) of a 3 Counties Alliance Partnership (3CAP) project to assess the effect of climate change on their highways policies and standards.Analysis of all areas of maintenance and operation of the interesting part VH. Introduction of an evaluation from comparable to those of sustainable development criteria system.

Ludovic Bouilloud, Dprévi/GCRI/Pôle Route, + DCLIM + CNRM, Changement climatique et infrastructures [51]

Synthetic presentation with snow cover and frost maps over France, based on different scenarios (temperature increase), and an hypothesis on climate evolution.Interesting to make projections in terms of winter maintenance, dimensioning an organization. The analysis compares the current situation with a climate evolution.

Anna K. Andersson, Winter Road Conditions and Traffic Accidents in Sweden and UK [52]

Present and Future Climate Scenarios Winter Road Conditions and Traffic Accidents in Sweden and UK. Present and Future Climate Scenarios.This thesis investigates the distribution of slippery roads in Sweden and the UK for the present climate and how this may be affected by climate change for the rest of the century. It also addresses future scenarios for traffic accidents and winter road maintenance. The purpose of this thesis is to get a better understanding of winter road conditions and relationships to motor vehicle accidents. A variety of scales are studied in this thesis ranging from nationwide studies in Sweden to smaller scale case studies in Sweden and the UK.Development of “Climate change and winter road maintenance: Will complacency be the new killer?” a lot of references.

Skuli Thordarson, Vegsn Consult, Climate Change and Winter Road Service [31]

Climate change will influence road traffic, maintenance and management in the near future, including winter road service. Global temperatures have risen by 0,74 °C during the last century, and are expected to rise by 1,1 to 6,4 °C by the end of this century. Most likely estimates for the next two decade predict a temperature rise of approximately half decree centigrade. Precipitation will increase and extreme wind speeds are believed to occur more often. Road owners and researchers in Europe are aware of this and research on the matter has been initiated in the different countries


2013R13ENand on the European level. Climate change impact on road management in general will vary geographically, and some issues may lead to beneficial outcome for the road management whereas other issues may demand relocation of resources and new thinking, also for the winter services.General approach concerning Nordic countries, with some proposals on winter maintenance. Other countries might be inspired to analyse similar specific issues.

Christopher Patten, Swedish Road Administration, Road owners getting to grips with Climate Change [53]

The road network is influenced by climate conditions. Climate change may result in more frequent and more intense rainfall, milder winters, warmer summers, and increases in wind speed and storm frequency. This will affect the road network in several ways. The adaptation of road networks to these changes is one of the important issues that road authorities need to address in the near future. This research programme aims to provide road authorities with the knowledge and tools necessary to “get to grips” with climate change and its effects on all elements of road management.

This initiatve is a trans-national joint research programme initiated by ERA-NET ROAD. Funding for the programme is being provided by 11 national road administrations in Europe including the NRA.The programme is being managed by the Swedish Road Administration under Swedish law and regulations. The projects commissioned were devised by consortia from various EU countries.Running project, with one objective being an “Improved local road winter index to assess maintenance needs and adaptation costs in climate change scenarios”.

Centre for Indigenous Environmental Resources, Winnipeg, Manitoba, Climate change impact on ice, winter roads, access trails, and Manitoba first nation [54]

The specific objectives of this research were to:

• Identify and document changes in ice conditions, winter roads and access trails;• Identify the economic, physical (personal health and safety), social, and cultural roles that river/

lake ice, winter roads and access trails play in Manitoba First Nations;• Assess the economic, physical, social, and cultural impacts that changes in ice conditions,

winter roads, and access trails have had and/or will have in the future on these communities;• Determine if strategies exist (and if any have been successfully implemented) for addressing

impacts associated with changing ice conditions, winter roads, and access trails; and,• Identify any barriers to, or drivers of, action regarding responses to changes in the winter road

and lake/river ice conditions.

Very intersting approach in terms on sustainable development. The method is adpted for northern countries and networks with low traffic, with useful ideas.

Mauduit LRPC Clermont Ferrand, Livet LRPC Nancy, Martin CEN, Impact of climate change on frost design and winter maintenance activities in France [11]

The purpose of this work is to quantify the evolution of current practices in frost design method, and in winter maintenance of roads in France for the coming century, in accordance with climate change. The work is based on climate simulation from the database od the French IMFREX project,


2013R13ENwich used the arpege-climate model. It simulates the climate evolution during the 21 century under A2 scenario of IPCC.

Approach linked to climate change and infrastructure, with a possible comparison with current situation and projections in terms of dimensioning and organizations.

Seppo Saarelainen, VTT, Finland, Adaptation to climate change in road management Climate Change and Road Management [55]

The vulnerability of road pavements and transport systems to climate change impacts depends on their impact response. Abnormal weather events like floods and storms have occurred in recent years, causing disturbance and damage. Important tasks for consideration are as follows: contingency planning, revision of design criteria, improvement of pavements and structures to ensure the service level and adaptation of maintenance operations.

Global road management approach with some winter maintenance elements.

R M Galbraith (Jacobs Babtie), D J Price (Jacobs Babtie), L Shackman (Scottish Executive), Scottish Road network climate change study summary report [43]

This report presents the predicted trends in climate change and the implications of these for the Scottish road network. Improving our knowledge of climate change and its impacts is essential to allow Scotland coping with the consequences of a changing climate. In common with other countries, Scotland is taking measures to protect the environment, tackling global warming and climate change by reducing emissions of the gases. Climate variation is now inevitable and all countries, Scotland included, need to take action to adapt.

Study containing an accurate map in terms of climate change impacts, with some details on roads and some recommendations. There are reports for the different road domains.

Sato, Noriyuki, Indiana University, Bloomington, Climate Change and its Potential Impact on Winter-Road Maintenance: Temporal Trends in Hazardous Temperature Days in the United States and Canada [56]

This paper describes how climatic changes will likely bring warmer air temperature in coming years. Although mean air temperature usually is employed to represent the magnitude of climatic change, changes in mean values are difficult to translate into changes in winter-road maintenance. Two variables derived from minimum and maximum air temperatures are used here in order to evaluate changes in winter-road maintenance over North America. Hazard days are those days with minimum temperatures recorded in a near-freezing temperature range, while below-freezing days are those days with maximum temperature not reaching 0°C (32°F). Over North America, there are differential trends of hazard days across the continent while there is a general decrease in the numbers of below-freezing days over the period 1948-2002. The regions with increasing numbers of hazard days are generally where minimum-temperature trends are positive. The regions with positive trends of below-freezing days cluster in the Ohio valley region. As climatic change takes place and the spatial distribution of hazard and below-freezing days changes, the types and intensity of winter-road maintenance activities will change. Allocation of resources and personnel need to be evaluated accordingly. By analyzing the recent 55 winter seasons of air-temperature data for the U.S. and Canada, the spatial distribution and trends of variables relevant to winter-road maintenance


2013R13ENare illustrated. The paper concludes by discussing a number of possible impacts of climate change on winter-road maintenance in the future.

Donna Reimchen, Reducing Maintenance Requirements on Permafrost-Affected Highways: Test Sections [24]

A significant amount of Yukon’s highway infrastructure is constructed on permafrost.

Yukon Highways and Public Works has undertaken an extensive research project aimed at finding cost-effective construction techniques to reduce permafrost thawing underneath the highway embankment. Test of Mitigation techniques.

Presentation on the structural aspect of roads.

Skuli Thordarson, Real-time frost depth forecast model for thaw-induced axle load limitation management [22]

To minimize road pavement and sub-base breakdown and simultaneously minimizing load restrictions, precise information and management during thaw periods is important. A network of road weather stations and sub-base frost depth sensors has been established in Iceland. The system has proven invaluable for real time monitoring of road conditions, both above and below the surface “ frost barriers” system management on structures

Diane Chaumont, evaluation of regional climate model simulations for winter transport-related information in the Saint Lawrence valley urban corridor [19]

Previous studies of climate change impacts on transport infrastructure in North America have usually been based on simulations from global climate models. The Ouranos Consortium (www.ouranos.ca) has a major research and development program to produce regional climate change simulations where the higher resolution allows the generation of more pertinent information for analysis of changes in the mean and variability of climate indicators. In addition, it is now possible to address uncertainties in projected climate changes using an ensemble of regional climate simulations to establish some idea of the degree of consistency in the response to projected global warming.

Local simulation of climate change to reach a better apprehension of local difficulties.

Michael Culp, Federal Highway Administration’s Strategy to Address Adaptation to Climate Change [20]

The Federal Highway Administration (FHWA) has taken a leadership position to address the growing gap surrounding adaptation. A working group was established in 2008 to create a strategy that addresses adaptation to the impacts of climate change. The purpose of the strategy is to solidify FHWA position on adaptation given the emerging understanding of the impending climate change impacts. The strategy also provides a means of communicating a policy direction for FHWA to all our stakeholders, especially state and local transportation agencies, as well as the public. The third objective of the strategy is to serve as a strategic foundation for future actions to be taken by FHWA. Prospective approach on the definition of organization policies.


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Hهkan Nordlander, What impact will climate change have on roads in Sweden and how to deal with it [23]

The result of the national analysis of risks and vulnerabilities due to the impact of climate change has given rise to a number of studies of the first effect of more water, in different forms. The main purpose of the project is to identify tunnels and parts of roads which are low-lying in comparison with sea level, and vulnerable parts of roads in relation to streaming surface water. Another part of the road structure at risk is the drainage system, which in future must be able to handle water in larger quantities than today. This problem is common to most parts of the country. The first climate change impact to be noticed, however, according to the scenarios which have been formulated, is extreme weather such as cloudburst. This will, for instance, affect slope stability and give rise to flooding.

Another problem caused by rising temperature, in the longer term, is the loss of frozen soil or permafrost. In the northern parts of Sweden, frozen soil is an important load-bearing capacity factor.

Approach concerning the effects on the road network and its environment (water management, slope stability, frost design, etc.).

***

As a global trend, climate variations were observed at the scale of a “snow operator”, meaning that these changes are extremely quick. Beyond subjective appreciations about winter severity, all weather and road weather data analysis (analysis of the number of snow occurrence on pavement, ice, risk, etc.) are indicating a temperature increase, less snow precipitations, and fewer and less snow cover on the ground. This trend started in the 1960’s, and could be applied to all countries concerned by winter maintenance.

Northern regions (North America, Scandinavia) are the most sensitive to this situation, and have conducted extended studies. The warming has many incidences on winter maintenance, with less operations, more ice occurrence with a greater number of cycles around 0°C and less stable situations, froast/thaw traffic management, permafrost management, management of traffic of frozen waters, slopes stability, to name a few.

In the case of temperate climates, winter maintenance management becomes more delicate, and needs accurate indicators. The warming trend is noticeable with a decrease in winter indexes, but is not equivalent to a reduction in winter maintenance.Climate projections are based on IPCC scenarios and some national scenarios, and in some cases use tools specific to some countries (Imfrex in France). Maps constructed based on these scenarios allow us to obtain trends for the 10, 30 or 50 coming years which allows for the evaluation of winter maintenance needs.

Some trials were made to apply the models on a region scale to get a better apprehension of the coming evolutions, and think about consistent decisions. Some approaches are taking into account interesting sustainable development aspects,


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looking at the evolution of winter maintenance along with climate evolution.

The transient period for the ten years to come might be hard to manage with the budgetary cuts.

The following effects on winter maintenance were mentioned in the literature:

• decrease in the number of frost days,• decrease in the amount of snow precipitations,• mild winters, and more humid ones,• decrease in winter maintenance,• decrease in the number of very cold days.

But these variations are heterogeneous, depend on regions (closer to sea shore, altitude, and so on). Some variations will certainly occur as time goes, but the 2009-2010 winter could be used as a reference as a very difficult winter in Europe. On the other hand, projections over extreme events are too difficult to be properly considered. In the case of Sweden, during the two winters 2008-2009 and 2009-2010, a very long period with snow all the time was observed, but also colder. No change in costs for winter maintenance were probably noticed, except for a redistribution of the costs from south further north.

Globally, snow data shows that winter constraints will decrease during the coming century. This reduction will have several impacts on winter maintenance activity. The first one will be the global winter maintenance cost. As snow occurrence, snow intensity, and snow duration decrease, the configuration of winter maintenance services will be modified. As an example, the most visible consequences will be the reduction of staff, of equipment (winter maintenance vehicles, snow ploughs, etc.), buildings and particularly de-icer shelters, and brine manufacturing devices, which will adapt to the number of winter maintenance operations. Moreover, duration of standby operation will go down, because the definition of the “winter period” will change. Currently, winter period duration corresponds to the period during which roughly 95% of snow occurrences happen, i.e. from the 15th of November to the 31st of March in France. Considering the variation in the winter phenomena, this period might either be extended, or be reduced.

The reduction should be of about 50% for buildings surfaces, de-icers shelters (number or surfaces), de-icers spreading. However, even with less events, roads users and managers will tend to face greater expectations and will accept less risk of accidents linked to meteorological phenomena. Service levels will tend to increase. This assumption would show that the number of winter maintenance vehicles, number of operation or amounts of de-icers spread, might not really decrease. Moreover, even if snow occurrences decrease, the number of winter maintenance


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vehicles might not really decrease in a significant part. Indeed, black-ice events, despite of the temperature increase, should always exist.

2.2. IMPACTS ON DE-ICERS CONSUMPTION AND USE

The de-icer consumption in France for the past decades, along with the increase in the road network and the severity index is shown in figure 11. There is no clear consistency between the winter severity and de-icer consumption. This is also enhanced by climate change and winter phenomena that confuses practices in winter management.

FIGURE 11 - SALT CONSUMPTION (IN THOUSANDS OF TONS) IN FRANCE OVER THE YEARS

WITH THE INCREASE IN THE ROAD NETWORK (- - - LINE), THE WINTER SEVERITY INDEX (BLACK LINE) AND A CONSUMPTION TREND (GREEN LINE)

De-icer orders are annually managed, and the ordered volumes depend on the consumption of the previous year. Without a clear forecast of the winter to come, the risk to under estimate the difficulties is great. A difficult balance and compromise has to be found between the levels of service (commitments of services to clear the network from snow and ice), budgetary and environmental constraints. These latest aspects are becoming more and more important among the criteria when tons of de-icers are purchased. Indeed, unless a de-icer supply is present in the neighbourhood, de-icers used for winter maintenance have to be carried by trucks, or shipped. The farther the source from the location of its final use, the greater the amount of greenhouse gases for its transportation. Impacts of de-icers are now acknowledged, but its quantification is not yet determined. Because of this additional constraint,


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environmental friendly de-icers appeared and were extensively presented at the 2010 PIARC International Winter Road Congress in Quebec City. Nevertheless, none seems to bring an appropriate answer in terms of efficiency, cost and impact on the environment, not to mention the compatibility with existing materials and practices. Additionally, if less de-icers are really needed, is it still relevant to look for alternatives?

2.3. IMPACTS ON MANPOWER

Another important impact will be the management of the staff. In fact, reduction of winter constraints will improve the management of winter maintenance staff. Currently, the legal framework often provides some difficulties in the service organisation, particularly in the case of significant and consecutive winter events, since the staff is temporarily required to work for durations greater than the legal hours. Mandatory rest periods might then induce staff vacancies.

Two assumptions can co-exist for the future:

• a limit not exceeding what the service is supposed to be, yielding less utilized sub-contractors and other complementary staff;

• this limit is reduced, then the design of the winter maintenance service will reduce in the same way.

For the second assumption, a global saving of money could be estimated. Currently, the global cost communicated by a French private motorway company is roughly of 8,000 €/km.

Because of the expected decrease in needs, the requirements for operators might decrease too. Snowploughs operators are trained to drive trucks equipped with blades and de-icer spreading systems, though it is not the case in all countries. If, as described before, the snow cover and snow fall intensity decreases in the yeas to come, a lack of practice and use with this material could be the first consequence.

In the coming future, many operators will retire, carrying with them vast knowledge of winter maintenance. Therefore, younger operators will have to build their own experience but based on a shorter winter duration, and often with more severe and sudden winter events. This raises the issue of placing individuals with limited knowledge and experience in charge of expensive materials and operations coupled with greater difficulties in obtaining forecasts of events makes winter maintnance less actractive to the work force. Financial incentives might be required inorder to achieve proper winter maintenance.


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2.4. IMPACTS ON COSTS

As described before, the shortening of the winter season with more sudden and severe events, winter maintenance organizations will have to change in terms of policy, practices and tools. On the short term, the difficulty in obtaining a good forecast from one winter to the next, though already present, is simply enhanced. The budget framework will be harder to establish, with direct consequences on all economical factors impacting winter maintenance (de-icer suppliers, contractors, and maintenance operators). It might also imply modification of maintenance policies, and in some cases not to clear road.

Long term impacts could apply to investments in equipment, such as road weather information systems (RWIS) and snowploughs. This equipment is expected to last between 10 to 20 years. Therefore, in the case of areas that might not be as affected by winters as they used to be in the past, the relevance of new investments could easily be raised. Likewise, maintenance and repairs of RWIS or vehicles and the renewal of contracts represent a significant part of the budget. The outlook for the years to come makes budget decisions difficult. Again, a compromise has to be found between the use of old and sometimes obsolete tools and the expense for obtaining new equipment that might not be optimially utilized. One solution might consist of utilizing modular or interchangable equipment as in the case for trucks. In the case of sensors embedded in road or on roadside, they could be use for different purposes such as summer maintenance, with the monitoring of thermal and water stress on the pavement structure.

Perhaps the most important decission is what level of service to provide for extreme weather events and also in the case of less severe winters, to decide which criteria will be implemented for decreasing manpower, equipment, and other winter maintenance resources.

2.5. SPECIFIC CASE OF URBAN AREAS, REMOTE AREAS

In the case of urban areas, the problem is the consistency of clearing roads to ease population mobility, and at the same time, major efforts are made to promote new mobility practices, based on public transportation (e.g. bus and tramways) and bicycles. Pedestrians are, as cyclists, part of the “whole travel picture”. Walking or cycling to ones vehicle/bus/tram/train is an important link in the travel trip just as walking or cycling the entire trip which illustrates the importance of this mode of travel. This means that a good winter standard is needed and mandatory on pedestrian and cycle paths (figure 12, next page).

One issue is the use of specific vehicles to cope with narrow lanes and urban equipments. So far, there is no real policy in urban winter maintenance. Each city


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defines more or less its own policy. The situation becomes magnified during high traffic peaks during commuting hours. The other issue is one of coordination. Entities in charge of urban winter maintenance do not necessarly belong to the same organization than those in charge of clearing highways or main roads. Therefore, either the cities gates could be still covered with snow while main roads are cleared, or the reverse. In either case, it might lead to main traffic disruptions.

(A) difference of clearing practices for cycles tracks and bus lanes (B) studded bike tyre

FIGURE 12 - WINTER MAINTENANCE IN URBAN AREAS

Nevertheless, the situation associated with sudden and severe winter events will not change anything. The idea would be to promote public transportation to avoid congestion, clearing bus corridors in priority. Because of the reduced speeds of these vehicles, the use of abrasives or studded tires could also be encouraged.

An aspect of amplification of climate change is the localized heat generated and retained in urban areas. This phenomenon is due to the local specific thermal inertia caused by buildings and surface coverage, inducing a poor sky view factor with permanent shaded areas, a reduction of vegetation, the occurrence of wind corridors. Depending on weather conditions, this could enhance (ice occurrence, snow transport) or reduce the effects of winter (natural melting of snow).

For remote areas, the main concern is to avoid the isolation of some people because of the distance between where they live and winter maintenance services centers. In this case, the difficulty is to use means (snowploughs, de-icers, abrasives, manpower, and other resources) for a reduced number of inhabitants with respect to a large geographical area. A balance has to be found between the expectations for mobility and the need to allocate specific and expensive means for small communities (case of fjords in Norway). In the case of extreme events, such as those inducing large consumption of abrasives or de-icers with a risk of shortage, some difficult decisions have to be taken by local authorities whether or not to clear specific zones. Another


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solution is to implement a high modularity on equipment, either dedicated to agriculture or other urban purposes (figure 13).

FIGURE 13 - EXAMPLES OF EQUIPMENT MODULARITY

3. IMPACTS ON ROAD INFRASTRUCTURES

3.1. CHANGES IN TEMPERATURE

The shorter time with frozen roads will cause problems as frozen roads have better load bearing capacity. This would mainly be a problem for the forest industry. The shorter time frozen also means less frost heave and less deformation. Higher temperatures will cause an increase in deformation. Milder winters with more rain instead of snow will result in less freeze/thaw in the south with more water in the road and more freeze/thawing cycles in the north with worse effects. The winter maintenance cost will probably decrease in the southern part of the Nordic countries but increase in the northern part. De-icing material will be required in areas were they were not specifically used (northern part). This will cause higher costs for bridge repair in the long run.

3.2. FROST/THAW CYCLES. FROST DIMENSIONING

According to Erlingsson, the main climate factors that affect pavement performance are temperature, water (moisture content) and frost/thaw cycles. A mechanistic empirical approach can predict performance of pavement structures. However, the accuracy of the method needs to be improved. Models describing the temperature dependency of material behaviour are working quite satisfactorily. Moisture content within the pavement structures varies in time and space. It has a great impact on the material behaviour of unbound granular material and soils and is therefore affecting the pavement performance. Enhanced knowledge is needed to improve our understanding of how water is affecting the pavement structure. Seasonal variation and frost/thaw cycles have great impact on the performance of pavements. No performance models are available that links frost/thaw with performance.


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The thermal design of road structures to address winter constraints can have major consequences. It all depends on the frost susceptibility of their subgrades, and of winter severity the pavements might face during their lifetime. Countries such as France have implemented a frost design method to test the compliance of the structure with frost/thaw cycles. Such check makes sure that the structure designed utilizing mechanical considerations will be able to withstand a given design winter without noticeable damage.

The pavement structure is designed for a given design frost index (IR). The pavement design is adjusted by either improving the frost susceptibility of materials, or by an increase in the thickness of frost resistant layers. In some other cases, when the criteria is not met thaw barriers will be installed to protect the structure from irreversible damage. Such solutions are implemented onto secondary network. Meteorological data were used to build frost index maps, and then maps of exceptional winter and of non exceptional rigorous winters.

A simple question could therefore be raised. Considering the climate change and meteorological evolutions, is frost dimensioning still as relevant as it used to be? Climate change will affect atmospheric parameters.

Some numerical calculations were run using the climate simulations database of the French IMFREX project (Impact of anthropic changes on the frequency of extreme phenomena of wind, of temperature and precipitations), along with the ARPEGE-CLIMAT (atmospheric climatic model developed by the French National Research Center of Météo-France for the forecast of climate evolution of a region of the globe) atmospheric model, with the A2 IPCC-scenario. With the calculations completed, a comparison could be made between the current maps of exceptional and non-exceptional rigorous winters (Figure 14, next page). In the case of France, a drastic decrease of the frost index would occur. This is based on a basic shift of temperature related to a mean temperature anomaly. This does not mean that extreme temperatures will follow the same trend.


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FIGURE 14 - MAPS OF EXCEPTIONAL (A) AND NON-EXCEPTIONAL RIGOROUS WINTERS (B)(YELLOW: 0-100°C.DAY, GREEN: 100-200°C.DAY, CLEAR BLUE: 200-300°C.DAY,

MID BLUE, DARK BLUE: >300°C.DAY)

If the frost index becomes less crucial, then pavement construction rules might be more lenient with a reduction in the amount of materials with characteristics to improve its frost susceptibility, or a decrease of layer’s thickness to withstand winters. The impact on the construction cost will be direct. One possible consequence is to have less expensive roads, but with a greater risk of damage in case of high frost. This might cause expensive repairs and a high probability to ruin the whole structure.

CURRENT SITUATION

FUTURE SITUATION ACCORDING TO A2 IPCC SCENARIO (TILL YEAR 2100)


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If the road is frozen the bearing capacity is much higher. To inform about that condition can be one way to have less damage/degradation on roads because the heavy vehicles can use the road when it is frozen. In spring time for example the road can be frozen at nights and early mornings when heavy vehicles can use the road. Notice in figure 15 that already in January the surface of that road had a temperature above 0˚C (red parts).

FIGURE 15 - TEMPERATURE IN THE ROAD CONSTRUCTION. ROAD SURFACE AT 0 CM. FROST MEASURED AUTOMATICALLY AT DIFFERENT DEPTH IN THE ROAD. (WWW.VTI.SE)

3.3. CONSTRUCTION AND CLIMATE CHANGES. OTHER ASPECTS

3.3.1. Longer construction season. Materials characteristics

The construction period was usually interrupted during wintertime, or as soon as the climatic conditions were not compatible with requirements either of materials, or of the techniques used. Furthermore, in the case of repairs, the choices have to be consistent with weather conditions, but also forecasts and trends for the coming months. In addition to these climatic conditions, were the compliance with budgets and fiscal years.

Such situations could have two consequences. The first one could be the acceptance of materials with characteristics no longer as strict and “noble” as in the past. Shorter periods of extreme conditions, or with a lower probability of occurance could


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promote less expensive choices. There is nevertheless no change in the nature of materials, since most of the time the mechanical performance is dependend on the structure below the pavement and these are not related to climate change and unaffected, unless there are specific increase in the traffic volume. The second aspect is the difficulty in identifying technical parameters due to sudden and intense variations. The trend is now observed in some regions for maintenance and repairs of infrastructure. Engineers and technicians are lacking perspectives and experiences regarding such extreme variations. Therefore the relevance and efficiency of some of the choices made now would only be know in the three to five coming years.

Nevertheless, the construction phases need the implementation and the integration of some materials which characteristics will improve the mechanical resistance and performance of the whole structure, allowing for instance the traffic of heavy trucks and other construction vehicles to build the different layers of a road. The success of this step is highly dependant on the temperature. The greater the temperature conditions, the better the schedule. When construction occurs too close to the wintertime, there might be serious consequences to the schedule. Climate change might cause some abrupt changes in temperature, and so accelerate, or slow down the occurrence of the appropriate moment where the mechanical performance of the structure is reached. Engineers are therefore taken into crossfire, with a schedule to respect, and mechanical performances to reach. This has to be done without the ability to rely on weather forecasts because of climate change instabilities. Figure 16, next page below indicates the consequences for two different road construction sites (a). In one case (b), the climate conditions were conventional and the schedule was respected. In the second case (c), some early snowfall during the fall season, that induced schedule disruption and improper behaviour of the base layer.


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FIGURE 16 - INCIDENCE OF UNUSUAL CLIMATIC CONDITIONS ON ROADS CONSTRUCTION SITE

Base layer subject to an early snowfall in NovemberBase layer with

conventional climate conditions

ROAD SECTION CUT

SURFACE LAYER

SHOULDERWEARING COURSE

BASE COURSE

ROAD BASE

ROAD BASE

SUB BASE

CAPPING LAYER

GROUND SUPPORT

FORMATION LEVEL

BASE COURSE


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4. CONCLUSIONS

Data from the past years indicated significant changes in temperature profiles, precipitation amounts, and more generally seasonal cycle perturbations. Snow events became more intense and sudden, and forecasts are getting more difficult. Based on GIEC scenarios, some significant changes could be identified, specifically for winter months.

Impacts on infrastructure were analysed through some examples such as de-icers consumption, manpower, and costs.

Consumption of de-icers kept on increasing despite mild winters. There is no clear consistency with winter severity. Budget constraints and cuts might cause a severe change in de-icer use. Experienced staff is now near retirement and part of the knowledge will leave with them. Furthermore, mild winters will provide the opportunity for organizations to set requirements that are not as strict as they once were, leading to substantial savings. The purchase and renewal of winter equipment seems to be conducted with a strategy based on modularity and optimisation, and to avoid the use of equipment solely dedicated to winter maintenance, except for some specific cases such as airports. Urban and remote areas are suffering of their specificities, and organizations would certainly be defined on experiences met now and years to come.

On the infrastructure topic, climate change might have major impact on current policies and practices. The case of the compliance with frost and thaw cycles is a good example. Based on GIEC projections, the question of frost susceptibility might no longer be an issue in most regions currently submitted to severe winters. In many situations, climate change has already started disruptions in construction schedules, up to the point that engineers are back in a learning phase on the implementation of technical solutions. Some innovations are also being implemented at large scale, including those in water management.

To handle the troubles resulting from climate change, winter road maintenance measures including snow removal or avalanche control systems need to be improved. Some proposals for the improvement follow :

• flexible snow removal systems indicated below could be adopted to handle unexpected heavy snowfalls in unusual locations;

• existing road maintenance jurisdictions for snow removal could be flexibly changed to meet the snow removal demand of areas with intense heavy snowfall;

• communities without snowfall could lend snow plows to nearby communities with heavy snowfalls;

• snow removal systems could be designed to cover a wide range of areas to efficiently


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assign snow removal fleets and equipment to places suffering snow disasters;• avalanche control systems need to be enforced to handle unusual avalanches

occurred by intense heavy snowfall;• to realize smooth traffic in case of sudden snowfall, the following weather or traffic

monitoring systems and emergency mutual aid systems are proposed:• snowfall monitoring system using CCTV cameras that can provide on site road

conditions to road users; • road traffic condition monitoring by probe car to collect real-time traffic information

to minimize traffic jams;• utilizing weather forecasts for timely road patrol or snow removal;• enforcement of road monitoring in cooperation with road administrators, private

companies and members of communities along the road toward establishing emergency mutual aid systems for snow disasters.

In the case of pavement and road construction, the suggestions are the following ones:

• the main climate factors that affect pavement performance are temperature, water (moisture content) and frost/thaw;

• a mechanistic empirical approach can predict performance of pavement structures. However, the accuracy of the method needs be improved;

• models describing the temperature dependency of material behaviour are working quite satisfactorily;

• moisture content within the pavement structures varies in time and space. It has a great impact on the material behaviour of unbound granular material and soils and is therefore affecting the pavement performance. Enhanced knowledge is needed to improve our understanding of how water is affecting the pavement structure;

• seasonal variation and frost/thaw cycles have large impact on the performance of pavements. No performance models are available that links frost thaw with performance.

5. BIBLIOGRAPHY / REFERENCES

[1] Fiona J. Warren, Elaine Barrow, Ryan Schwartz, Jean Andrey, Brian Mills, Dieter Riedel. Impacts et adaptation liés aux changements climatiques : perspective canadienne. ISBN : 0-662-88032-3 (http://adaptation.rncan.gc.ca/perspective_f.asp). 190 p.

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[3] Ambio, 2004, Special issue on Swedish Regional Climate Modeling Programme.Vol. 33.


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[4] Bernes, C., 2003. En varmare värld. Monitor 18, Naturvårdsverket, Stockholm, Sverige.

[5] Fumihiro Hara and Yasuhiro Kaneda Effects of Climate Change on Winter Road Environment in Hokkaido. PIARC Seminar “Management of Winter service in an extreme continental climate country” in Ulan Bator, Mongolia, April 2011.

[6] Christensen, J.H., B. Hewitson, A. Busuioc, A. Chen, X. Gao, I. Held, R. Jones, R.K. Kolli, W.-T. Kwon, R. Laprise, V. Magaña Rueda, L. Mearns, C.G. Menéndez, J. Räisänen, A. Rinke, A. Sarr and P. Whetton, 2007: Regional Climate Projections. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. CambridgeUniversity Press, Cambridge, United Kingdom and New York, NY, USA.

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[13] Kjellström, E., Bärring, L., Jacob, D., Jones, R., Lenderink, G and Schär, C., 2007. Modelling daily temperature extremes: Recent climate and future changes over Europe. Climatic Change.Vol. 81.doi:10007/s10584-006-9220-5

[14] Nakićenović, N., Alcamo, J., Davis, G., de Vries, B., Fenhann, J., Gaffin, S., Gregory, K., Grübler, A., et al., 2000. Emission scenarios. A Special Report of Working Group III of the Intergovernmental Panel on Climate Change. Cambridge University Press, 599 pp.

[15] Räisänen, J., U. Hansson, A. Ullerstig, R. Döscher, L.P. Graham, C. Jones, H.E.M. Meier, P. Samuelsson, U. Willén, 2004. European climate in the late 21st century: regional simulations with two driving global models and two forcing scenarios. Clim. Dyn., 22, 13-31.

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[17] NRA (Nordic Road Association). Climate Change in Nordic Countries – influence on roads– adaptation of road administrations. Unpublished report from 2008-03-25 http://www.vegagerdin.is/nvf41.nsfseeprosjekterklimaforandringar (in Nordic languages). 64 pages. Summary in English Climate Change – Influence on Roads – Adaptation of Road Administrations. 9 pages.

[18] Juan Pernia, Jeffrey Chapin, Max Perchanok. Adaptation des restrictions de charge saisonnières aux changements climatiques. XIIIrd Winter Road Congress - Quebec City 2010

[19] D. Chaumont, R.D. Brown. Analyse de simulations régionales du climat et d’indices climatqiues associés au transport routier dans le sud du Québec. XIIIrd Winter Road Congress - Quebec City 2010

[20] M. Culp, P. Pisano, F. Klein. Élaboration d’une stratégie d’adaptation au changement climatique par l’administration fédérale des routes. XIIIrd Winter Road Congress - Quebec City 2010

[21] N. Andre, D. Hansen & P. Bartley . Manuel de construction et d’entretien des chemins de glace. XIIIrd Winter Road Congress - Quebec City 2010

[22] S. Thordarson, N. Jonasson, E. Sveinbjornsson, A. H. Thorolfsson, G. O. Bjornsson. Modèle de prévisions en temps réel de la profondeur de gelpour la gestion des limitations de la charge à l’essieu. XIIIrd Winter Road Congress - Quebec City 2010


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[23] H. Nordlander. Quelles répercussions le changement climatique aura-t-il sur les routes suédoises et comment le gérer ?. XIIIrd Winter Road Congress - Quebec City 2010

[24] D. Reimchen, B. Stanley et R. Walsh, G. Doré, D. Fortier. Réduction des besoins d’entretien des routes touchées par la dégradation du pergélisol : Tronçons d’essai de la route de l’Alaska (Yukon). XIIIrd Winter Road Congress - Quebec City 2010

[25] P.O. Lausecker, C. Mauduit, E. Jacquot. Méthodologie pour l’analyse spatiale des impacts des fondants routiers sur les eaux de surface. XIIIrd Winter Road Congress - Quebec City 2010

[26] M. Satin. Recherche pour minimiser les impacts écologiques des sels de voirie. XIIIrd Winter Road Congress - Quebec City 2010

[27] Y. Yamamoto, S. Sone, K. Kimura, et Y. Namikawa. Recherche sur l’impact environnemental des sels de dégivrage. XIIIrd Winter Road Congress - Quebec City 2010

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[48] Lee Chapman, University of Birmingham, UK Anna Andersson, Goteborg University, Sweden Climate change and winter road maintenance: Will complacency be the new killer?

[49] Chris Plumb, Highways Agency UK, The effects of Predicted Climate Change on Winter Service Operations

[50] Caroline Walters, The effect of Climate Change on 3CAP’s Highway Network Policies and Standards

[51] Ludovic Bouilloud, Dprévi/GCRI/Pôle Route, + DCLIM + CNRM, Changement climatique et infrastructures

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[53] Christopher Patten, Swedish Road Administration, Road owners getting to grips with Climate Change

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[55] Seppo Saarelainen, VTT, Finland, Adaptation to climate change in road management Climate Change and Road Management

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