Main menu

email noborder 35pixel twitter noborder 35pixel

Facebook noborder 35pixel

Share-the-Road-Share-the-Experience-horizontal-logo 500px horizontal-banner



Take-the-Pledge-Email-Banner website-banner-850-x-350

Forum, Panel to Discuss Proposed Changes in Speed Limits on Michigan Roads

spee limit signFrom our partners at the Michigan Environmental Council

A forum to discuss issues relevant to proposed changes in Michigan speed limits will take place Wednesday, January 29 from 10 to 11:30 a.m. at the Michigan Municipal League offices at 208 N. Capitol Ave. in Lansing.

The public is invited, and RSVPs are requested.

The forum will be moderated by Tim Fischer, of the Transportation for Michigan coalition (Trans4M) and the Michigan Environmental Council.

Panelists will include Lt. Gary Megee of the Michigan State Police, Jim Walker of the National Motorists Association, Suzanne Schulz of the City of Grand Rapids Planning Department, Richard Murphy of the Michigan Suburbs Alliance, Adrianna Jordan of the Michigan Fitness Foundation, and Carolyn Grawi of the Ann Arbor Center for Independent Living.

How Michigan's speed limits are set has far-reaching consequences for Michiganders, thus, concerns run deep and diverge widely.

Attend the forum to learn:

  • What roadways are affected by the 85th percentile method of setting speed limits?
  • What are the perspectives of various stakeholders regarding this method?
  • What is the research behind these perspectives?

Please RSVP with this signup form.


Background on potential advantages and disadvantages of the 85th percentile method of setting speed limits
For resources, see this link.

Possible advantages:

Some are calling for a reduction in "speed traps," which they say hurt the working poor who can ill afford to pay the tickets. They say speed traps exist to generate revenue for the courts that prosecute them, not to increase safety. Studies show that simply lowering speed limits doesn't decrease accidents (see Martin R. Parker. "Comparison of Speed Zoning Procedures and their Effectiveness: Final Report." Michigan Department of Transportation - Traffic and Safety Division, 1992 which studied roads across the country both before and after posted limits were lowered or raised. The study found that neither speeds nor accident rates changed significantly after posted speeds were changed).

Advantages of the 85th percentile method include the idea that increasing speed limits frees up police to go after serious speeders. This is based on the concept that drivers naturally go the speed that is safe for a particular roadway, depending on factors such as visibility and road width. To determine what this safe and comfortable speed is for a particular stretch of roadway, measurements are taken of passing cars and their speeds are plotted on a distribution curve. The 85th percentile is at the "head of the pack," faster than 85% of the other drivers, which some studies show is safest. This is because lane-changing is reduced.

Some say that even if posted speeds "creep up" due to the 85th percentile rule, people will adjust to the increases because the changes will be gradual. They say the "pedestrian safety crisis" is overblown, i.e. car and pedestrian fatalities have decreased over time, and most pedestrian fatalities are the fault of the pedestrian, anyway.

School zones, city centers, and subdivisions are excluded from the 85th percentile method rule. On roadways where limits can increase, communities can build infrastructure to separate pedestrians from cars.

Possible disadvantages:

Numerous Michigan roadways have the potential to have their speed limit raised, including the many non-subdivision residential areas that have significant pedestrian use. Money is not available to build infrastructure such as bridges to separate pedestrians from traffic in all these areas.

Although the Parker study did include pedestrian accidents in the data set, the roads it studied were not heavily used by pedestrians in the first place, so there are questions about whether it should be used to prove overall safety of the 85th percentile method. On roadways where pedestrian use is a goal, some say the vulnerability of pedestrians should preclude raising speed limits regardless if drivers feel comfortable driving faster (the U. S. Department of Transportation says pedestrian fatality rates rise exponentially as car speeds increase, jumping from 40 to 80% as speeds rise only 10 mph, from 30 to 40 mph).

The Parker study does not take into account that overall mortality rates increase with more driving and less walking, due to diseases related to inactivity. It also does not factor in our aging population and the explosion in distracted driving.

Numerous local communities want to maintain lower limits on roadways where their citizens desire increased pedestrian safety. Police already focus on higher speeders (being physically unable to pull over every speeder), a point against the "free up the police" argument. Although the Parker study did show that simply lowering limits on posted signs isn't effective, it did not measure the efficacy of attempts to educate drivers, through measures such as "This Is Your Speed" signs, which other studies have shown are effective.

When speeds are measured to determine a roadway's 85th percentile, cars that are slowing for bikes or pedestrians are not counted. Some fear that as speeds "creep up," so will car use. In addition to pedestrian safety issues, the carbon footprint of the 85th percentile method is a concern-through the discouragement of non-motorized travel, and the decrease of fuel efficiency at higher speeds.






Share MI Roads is a campaign developed by the League of Michigan Bicyclists in collaboration with a diverse network of partners.
Share MI Roads is supported through funding by Transportation For Michigan, individual donors, and sponsors.