Opinion / Transportation safety

Why Class IV separated bikeways are the safest choice on high-risk streets

When bicyclists must travel beside significant motor-vehicle traffic, Class IV separated bikeways provide the strongest protection because they do more than designate space. They place a physical element between a person on a bicycle and a moving vehicle, and that distinction still matters if a collision occurs.

Paint communicates. Physical separation intervenes.

FHWA reports that converting traditional or flush-buffered bicycle lanes to separated lanes with flexible delineator posts can reduce bicycle-vehicle crashes by up to 53 percent. The result varies by context and design, but it shows that vertical separation is not merely cosmetic.

Physical separation can strengthen the post-collision record

A curb or substantial separator creates a fixed, measurable feature that may preserve tire marks, scuffs, gouges, debris, displaced elements, and vehicle damage. Qualified reconstruction professionals can combine that evidence with separator geometry, video, witness statements, vehicle data, and accepted methods to evaluate speed, trajectory, and approach angle. The evidence can inform a liability analysis, but it does not decide negligence or fault by itself.