Improved Safety and Efficiency of Protected/Permitted Right Turns for Bicycles in the Pacific Northwest

Abstract

Conflict between bicycles and right-turning vehicles on the approaches to intersections is a critical safety concern in urban environments. To understand the safety and operational implications of using protected-permitted right turns (PPRT), a full-scale bicycling simulator experiment was performed. The velocity and lateral position of bicyclists were evaluated during conflicts between bicycles and right-turning vehicles. Two independent variables were analyzed: the signal indication for right-turning vehicles (circular red or green, solid red or green arrow and flashing yellow arrow) and the pavement markings in the conflict area (white lane markings with no supplemental pavement color and white lane markings with solid green pavement applied in the conflict area). Forty-eight participants (24 women and 24 men) completed the experiment. Signal indications and pavement markings had statistically significant effects on bicycle velocity and lateral position, but these effects varied at different levels of the independent variables. Use of PPRT phasing in conjunction with colored pavement markings was associated with increased bicyclist conflict with right-turning vehicles, whereas PPRT phasing with no supplemental colored pavement markings was associated with improved bicyclist safety. The results provide guidance to transportation professionals about how traffic control devices could be applied to conflict areas before signalized intersections.