Effect of the 65-MPH Speed Limit on Vehicle Speeds in Michigan

摘要

The report describes a study of vehicle speeds on various highways in the State of Michigan before and after the change to 65 mph was implemented. Speed measurements were made at a number of sites on various classes of roads on three occasions, once before the effective date of the speed change, and twice after. The results of the study indicate that speed changes on freeways where the speed limit was increased averaged 1 to 2 mph. There was some evidence of a speed increase of about the same magnitude on other four-lane roads linked directly to these freeways. There was no evidence of a carryover to nearby two-lane roads.