-
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
-
Proper v. Improper Posting
-
Proper v. Improper Posting
-
Proper v. Improper Posting
-
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)
Speed Number of Vehicles Additional
55 or less
I
56
I
57
IIIII
58
IIIIIIIII
59
IIII
60
IIIIIIIIIIII
61
IIIIIIIII
62
IIIIIIIII
63
IIIIIIIIIIIII
64
IIIIIIIIIIIIIIIIIIIIII
65
IIIIIIIIIIIIIII
66
IIIIIIIIIIIIIIIII
67
IIIIIIIIIIIIIIIIIIIII
68
IIIIIIIIIIIIIIIIIIIIIIIIIIII
69
IIIIIIIIIIIIIIIIIIIIII
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
-
Proper v. Improper Posting
SPEED STUDY, POSTED 25MPH ROAD
Speed Number of Vehicles Additional
-
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.