Protected bicycle lanes marked with simple traffic cones and plastic delineators were associated with a reduction in average maximum speeds of 20 to 30 percent. 

The findings come from an analysis of almost 10,000 cars during a temporary pilot demonstration project in Asbury Park, N.J., where bike lanes were both painted and delineated with traffic cones. The study incorporated 24-hour video footage of the intersection for 10 dates in March and April 2022. 

“The Traffic Calming Effect of Delineated Bicycle Lanes,” by nine researchers at Rutgers University, including the Edward J. Bloustein School of Planning and Public Policy, will be published in the June volume of the Journal of Urban Mobility. 

Average top speeds of vehicles dropped by 28 percent, by 21 percent for vehicles turning right, and by up to 8 percent for drivers going straight. Painted-only bike lanes were also associated with a reduction of 11 to 15 percent solely for vehicles turning right. Traffic moving perpendicular to the bicycle lane experienced no decrease in speeds. Bicycle lanes with traffic delineators will have a stronger traffic calming effect, such as reductions in speed, than with painted-only bike lanes, according to the study. 

“In the context of traffic safety and Vision Zero initiatives, this finding is significant in that it suggests that delineated bike lanes can reduce traffic speeds, making the overall road environment safer for all. The pop-up bike lane reduced the traffic lane width and created a sharper turning radius, which likely served as a traffic calming mechanism.” 

The complete report can be found here.