Speed studies are conducted to determine the 85th percentile speed and identify reasonable driver behavior for a particular stretch of roadway. The speed study is one part of an engineering and traffic investigation — a nationally accepted guideline for setting speed limits.
The survey team in the field also identifies and considers other factors — including traffic crash data, traffic volumes, roadside development, roadway configuration and condition, number of intersections and driveways, sidewalks, and any other factors that may influence all types of road users.
“Our comprehensive analysis in determining speed limits relies heavily on identifying normal and safe driver behavior, and whether or not a speed limit is realistic,” State Police Director Col. Kriste Kibbey Etue said.
For more information on how speed limits are set, visit www.michigan.gov/speedlimits.