By Charles Pekow — If the police vigorously enforce passing laws, it will increase compliance, a federal review found. Grand Rapids, MI instituted a law requiring motorists to give bicyclists a five-foot clearance when passing. Knoxville, TN implemented a three-foot law. Both cities actively publicized the law. Police in both towns rode bikes with ultrasound monitors to judge how far away the autos actually passed. While 26 percent of motorists violated the five-foot rule, only five percent violated the three-foot rule.
When a motorist passed too closely, the police officer on the bike would radio a squad car to stop the motorist. Police in both cities often just gave warnings instead of tickets. But they found at the end of the study that motorists were more likely to comply with the laws. The National Highway Traffic Safety Administration reported the results in Evaluating High-Visibility Enforcement of Bicycle Passing Laws (https://rosap.ntl.bts.gov/view/dot/60877).