Wayne State University researchers are nearing completion of a year-long study to determine whether different freeway speed limits for cars and trucks make roadways safer. Three scenarios are being evaluated including maintaining the current speed limit differential of 10 mph lower for trucks and buses, decreasing the differential from 10 mph to 5 mph, and making a uniform speed limit for all vehicles. Funded with a grant from the Michigan Department of Transportation (MDOT), the study involves reviewing previous research, surveying trucking industry groups, collecting historical and new field data from Michigan and other states, and performing statistical analysis of the data.

Martin Parker, PE, a Senior Transportation Engineer in our Taylor, MI, office, has been assisting with study research and documentation, lending his 48 years of traffic engineering and safety management experience. He will also review the final report entitled, “Evaluating Differential and Non-Differential Freeway Truck and Bus Speed Limits” that will be delivered to MDOT officials to use in making policy recommendations to Michigan legislators.