Michigan speeds focus of House committee

December 2, 2020

Keith Goble


A Michigan House bill that is touted to clear up confusion in state law about how state and local roadway speeds are set is scheduled to receive consideration this week.

The House Transportation Committee will meet on Thursday, Dec. 3, to again discuss a bill to revise how the state observes the 85th percentile speed rule – the speed at or below which 85% of vehicles travel in free-flowing traffic.

Michigan law states that an engineering and safety study be conducted to modify a speed limit. Additionally, speeds on state and local roads must be rounded to the nearest multiple of 5 mph.

Statute also prohibits a speed limit from being set below the 50th percentile speed of free-flowing traffic under ideal conditions on the fastest portion of the affected highway segment.

‘Flexibility’ on setting speeds

Sponsored by Rep. Bradley Slagh, R-Zeeland, the bill would free up the state to round down the 85th percentile speed when necessary.

In August, Slagh provided the committee with the example of the 85th percentile speed on a roadway to be 37.6 mph. He said his bill would give the state flexibility to set the speed at 35, instead of being required to bump it up to 40.

The legislation would also remove the reference to an engineering and safety study to be conducted to alter a speed limit. Instead, a modified speed limit would be determined in accordance with traffic engineering practices that provide “an objective analysis of the characteristics of the highway.”

Additionally, HB4733 would permit a speed limit to be set below the 85th percentile if an engineering and safety study showed a situation with hazards to public safety that are not reflected by the 85th percentile speed.

Slagh said roadways near schools, parks or churches would qualify under the special privilege. LL

More Land Line coverage of news from Michigan is available.