Setting Municipal Speed Limits

Setting Municipal Speed Limits:Compliance with 2006 PA 85

2007 ITE Michigan Section Technical SessionDecember 6, 2007Sgt. Lance R. CookMr. Jim WalkerMichigan State PoliceJCW ConsultingTraffic Services Section

Background InformationHow We Arrived at Where We Are Today

Background InformationTraffic engineeringespecially setting speed limitsis largely counterintuitivePublic and elected officials do not understandtend to want solutions that provide a false sense of security over solutions that actually create safer drivingTraffic engineers are often threatened or coerced into political solutions for perceived problems

Background InformationRecurring issues with speed limitsGravel roadsState and county roads inside citiesResidence and business districtsDefinitions stretched or misappliedAttempts to establish 15 mph speed limitsRoad rage and aggressive drivingTownship involvement

Background Information2006 PA 19 (HB 5104) Rep. Caswell2006 PA 85 (HB 5240) Rep. Palmer2006 PA 86 (HB 5241) Rep. Palmer

Background InformationNew laws helped to raise public awareness of the problemsNew laws give traffic engineers greater ability to make good decisions for safety while reducing or eliminating ability to make decisions based solely on politics

Section 1Laws Authorizing the Establishment of Speed Limits by Municipalities

Authority for Municipal Speed LimitsMCL 257.606(1)(k) Increase prima facie speed limits as authorized in this actMCL 257.608 Establish MMUTCD by MSP and MDOTMCL 257.610(a) Apply MMUTCD to local ordinances and related traffic control devicesMCL 257.610(b) Authority of MDOT to withhold gas tax money for noncompliance

Authority for Municipal Speed Limits (continued)MCL 257.627(2)(a) Prima facie speed limit of 25 mph in Business District as defined in MCL 257.5MCL 257.627(2)(b) Prima facie speed limit of 25 mph in public parkMCL 257.627(2)(c) Prima facie speed limit of 25 mph within platted subdivision per MCL 560.101 et seq. or condominium complex per MCL 559.101 et seq.

Authority for Municipal Speed Limits (continued)MCL 257.627(2)(d) Prima facie speed limit of 25 mph for 60+ vehicular access points within mileMCL 257.627(2)(e) Prima facie speed limit of 35 mph for 45-59 vehicular access points within mileMCL 257.627(2)(f) Prima facie speed limit of 45 mph for 30-44 vehicular access points within mile

Authority for Municipal Speed Limits (continued)MCL 257.627(3) Speed limits per subsection (2) are prima facieMCL 257.627(10) Requires speed limits established per this section to be properly posted or default to 55 mph per 628(1)MCL 257.627(12) Allows a traffic and engineering investigationMCL 257.627(13) Defines vehicular access point as driveway or intersecting roadway

Authority for Municipal Speed Limits (continued)MCL 257.629(1) Allows for establishment or increase of speed limits on municipal streets per the following limitations:(a) Increases within business district require designation as a through street(b) Increases require adequate signs(c) Speed limits established outside of business districts must be consistent with limits established in MCL 257.627(2)

Authority for Municipal Speed Limits (continued)MCL 257.629(2) Gives MDOT authority to establish speed limits on state roads within municipal limitsMCL 257.629(3) Allows for prima facie speed limit of 15 mph in public parksMCL 257.629(4) Allows for prima facie speed limit of 25 mph on streets adjacent to public park or playgroundMCL 257.629(7) Defines local authority as a city or village except for 257.629(4)

Authority for Municipal Speed Limits (continued)MCL 257.951(1) Allows MSP to promulgate Uniform Traffic Code for Cities, Townships, and Villages (UTC), and allows municipalities to adopt by referenceSubservient to MVC; any conflicts with MVC or other state law render UTC section null and void

Section 2Mechanism for the Establishment of Speed Limits by Municipalities

Mechanism for Establishment of Municipal Speed LimitsMCL 257.610 requires municipal traffic control devices to conform to MMUTCDMMUTCD 2B.13 requires an engineering study made in accordance with established traffic engineering principlesWarrants for speed limits from MMUTCD include:Within 5 mph of 85th percentile speed of free-flowing trafficMay consider other factors

Mechanism for Establishment of Municipal Speed Limits (continued)UTC R 28.1126 Rule 126 requires all duties of traffic engineer to be in accordance with standard and accepted engineering practices as found in the ITE Traffic Engineering Handbook, 5th EditionUTC R 28.1153 Rule 153 requires all traffic control orders to be in accordance with standard and accepted engineering practices as adopted in R 28.1126

Mechanism for Establishment of Municipal Speed Limits (continued)Primary warrants for speed limits from ITE Handbook 5th Edition include 85th percentile of free-flowing traffic and upper limit of 10 mph pace

Mechanism for Establishment of Municipal Speed Limits (continued)R 28.1153 Rule 153(1) requires a Traffic Control Order to be filed with municipal clerk and adequate signs erected to become effectiveR 28.1153 Rule 153(2) allows temporary TCOs for 90 daysR 28.1153 Rule 153(7) Temporary TCOs must also conform to ITE standardsRule 153 language intended by MSP to apply 257.628 TCO process to municipal TCOs

Section 3Case Studies and Effects of Proper and Improper Posting of Speed Limits

Proper v. Improper Posting


SPEED STUDY, POSTED 55MPH FREEWAY(e/b)

Speed Number of Vehicles Additional

55 or less

IIIII

(Speed Limit

56

IIII

57

IIIII

58

IIIIIIII

59

IIIIIIIIIIIIII

60

IIIIIIIIIIIIII

61

IIIIIIIIIIIIIIII

62

IIIIIIIIIIIII

63

IIIIIIIIIIIIIIIIIIIIII

64

IIIIIIIIIIIIIIIIIIIII

65

IIIIIIIIIIIIIIIIII

+10mph

66

IIIIIIIIIIIII

67

IIIIII

68

IIIIIIIIIIIIIIIIIII

69

IIIIIIIIIIII

70

IIIIIIIIIIIIIIII

+15mph

71

IIIIIIIIIIIIIIIIIIII

72

IIIIIIIIIIIIIIIIII

73

IIIIIIIIIII

74

IIIIIIIIIIIIIII

(85th percentile

75

IIIIIIIII

+20mph

76

IIIIIIIII

77

IIIIIII

78

IIII

79

III

80

IIIII

+25mph

81

II

82

83

I

+28mph

84 or more

309 Vehicles, 20 minute study

SPEED STUDY, POSTED 70MPH FREEWAY(E/b)


55 or less

I

56

I

57

IIIII

58

IIIIIIIII

59

IIII

60

IIIIIIIIIIII

61

IIIIIIIII

62

IIIIIIIII

63

IIIIIIIIIIIII

64


65

IIIIIIIIIIIIIII

66

IIIIIIIIIIIIIIIII

67

IIIIIIIIIIIIIIIIIIIII

68

IIIIIIIIIIIIIIIIIIIIIIIIIIII

69


70

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

(Speed Limit

71

IIIIIIIIIIIIIIIIIIIIIIIIIIII

72

IIIIIIIIIIIIIIIIIIIIIIII

73

IIIIIIIIIIIIIII

(85th Percentile

74

IIIIIIIIIIIIII

75

IIIII

+5mph

76

IIIIIIII

77

IIIIII

78

II

79

IIII

80

I

+10mph

81

I

+11mph

82

83

I

+13mph

84 or more

III

+14,21mph

333 Vehicles, 18 minute study


SPEED STUDY, POSTED 25MPH ROAD


ResourcesManuals and Internet Links

Resources

Group DiscussionQuestions and Comments

Contact InformationSgt. Lance R. CookMichigan State PoliceTraffic Services Section4000 Collins RoadLansing, MI 48909(517) [email protected]. Jim WalkerJCW Consulting2050 Camelot RoadAnn Arbor, MI 48104(734) [email protected]

Brief introduction of speakers and overview of presentationProblem can be much worse in areas where the police chief is the de facto traffic engineer, with no technical training in the discipline.A whole generation has been brought up believing the 1974 NHTSA propaganda during the counterproductive NMSL eraMany city engineers feel they have to please their mayor or city council, even to the point of completely ignoring proper engineering standards.Bills introduced almost every legislative session attempting to fix one or more of the problems.Counterintuitive--many solutions did/would make some problems worse

Oakland County gravel roads mislabeled as residence districts in past years (definitions now changed by PA85)Downtown designations as business districts by virtue of signEast Lansing lawsuitPublic misperception of causes of road rage/aggressive drivingMcNitt Acttownships dont own or control roads, yet legislature recently included them in the processPA 19 Raised truck speeds to 60 mph on freeways with 70 mph speed limit for cars (political influence forced 60 instead of 65 in original bill)PA 85 Repealed definition of Residence District, amended definition of Business District, and established access point formulaPA 86 Amended Pupil Transportation Act to match changes to MVC for School Bus speed limits

Legislators approached MSP after repeated opposition to previous bills to work for a solution to many of the issuesMSP, MDOT, NMA, and other groups educated a small group of legislators, including Caswell and Palmer on engineering and safetyThere were several compromises made, but these three laws are a huge step in the right directionPA85 provides a way for township officials to opt out of speed limits, a good choice for many of them for political cover.Nationwide, the motoring public is becoming more educated about how speed limits are set.The internet has made unbiased traffic safety engineering studies widely available, so public can see what is being done wrong.Instead of attacking the police officers credibility, the RADAR unit, or the circumstances of the individual stop, people are beginning to attack improperly posted speed limits.One court case has the potential to expose an entire speed limit as invalid and another one is probably coming soon with a well known engineer.Can result in a domino effect, exposing a municipalitys entire system as weak or invalid (Lansing, Grand Ledge, Ann Arbor, etc.).The city of Chelsea looked at the new law, agreed it was in effect, and did proper TCOs under 257.951 to re-set proper limits on many of their major collectors and arterials that closely reflect 85th percentile speeds.Most of the speed limits over next several slides apply to state, county, or municipal roads unless otherwise mentioned.Discuss repeal of definition of Residence District and changes to definition of Business District.Applies to state, county, or municipal roadsApplies to state, county, or municipal roads.Subsection (11) refers to MCL 257.628(1), and is specific to county and state roads speed limits as established by the TCO process.Discuss general speed limit from MCL 257.628(1).Discuss studies leading up to access point formula -- compared actual 85th percentile speeds to actual access point counts. While there are some exceptions on some roads, the formula sets many roads at or very close to the 85th percentile speed of free flowing traffic under good conditions.Discuss changes to definition of business district.Discuss the term adequate sign.Reinforce access point formula in MCL 257.627(2).Discuss township authority for county roads.Discuss relationship of MVC, UTC, and MMUTCDMUNIPALITIES CAN GAIN AUTHORITY TO DO TCOs by adopting 257.951, but the UTC reinforces that the traffic and engineering studies must be done according to standard and accepted engineering practices in the ITE manual.Describe other factors.Discuss relationship of other factors to 85th percentile and problem with double counting of other factors.Other factors should ONLY be used when they are not readily apparent to most drivers. Obvious factors like parked cars, common bike and pedestrian traffic, narrow lanes, visible curves, etc. are already taken into account in the 85th percentile speeds chosen.Hidden hazards or brief parts of a segment that should be slower than the rest of a long segment should use proper warning signs and advisory speeds. It is incorrect to post a 2 mile stretch of road with the conservative design speed needed for just the 150 yard hazard in the center.Discuss police chief as de facto traffic engineer if none appointed.Discuss some issues with various municipalities, i.e. Auburn Hills, Grand Ledge, Ann Arbor, Lansing, etc.Properly done, it should not be acceptable to post speed limits at the 4th or 22nd percentile speed of free flowing traffic under good conditions.If the engineer uses proper practices, posted limits will define the normal, prudent and safe driving practices of the majority of drivers as legal, rather than defining 67% or 82% or 96% of the drivers as in violation of an improperly low limit.Discuss lack of mechanism to adjust speed limits if UTC not adopted.The drivers at the least risk of having a crash tend to be in the 60th to 90th percentile speed ranges, but these drivers are above the posted speed limit in a great percentage of cases. Why is it OK for anyone to define the safest drivers as in violators subject to very large financial penalties from the courts and their insurance companies? Safe drivers should be allowed to proceed without fear of sanctions.Normal Distribution or Bell CurveNote that one standard deviation above the mean closely approximates 85th percentile with 68% of drivers within one standard deviation of mean.Note that a 16th percentile speed posted limit is the virtual inverse of proper procedure and defines the entire 68% center of the bell curve as illegal, a practice that is difficult to defend in engineering terms. Yet, this is what many politicians want to happen, to satisfy citizens that know absolutely nothing about the science of traffic safety engineering.Freeway raised from 55 mph to 70 mph.Note tightening of distribution around mean.This section of I-69 in Flint now flows much more smoothly, with better lane courtesy.Speed limit raised from 25 mph to 35 mph.Note almost no change in distribution, except now 90% of drivers are within 5 mph of posted limit, compared to almost 100% in violation under previous limit.No posted limit that defines 80% or 90+% of normal, safe drivers as violators can ever command respect. These practices degrade the overall respect for traffic laws and for law enforcement officers in general which is a very poor practice for society.

Documents

Setting Municipal Speed Limits