1374146 - Bicycle Silhouette Signal Faces: Results from a Before and After Experimental Study

Bicycle networks are an integral part of a sustainable and multimodal community. Communities across the country have been aiming to improve bicycle networks by implementing innovative solutions. One innovative solution, the bicycle signal face, has been highlighted as a way to provide enhanced clarity for all road-users and safety for cyclists. Currently, cities can use a bicycle signal face as long as it complies with the Manual of Uniform Traffic Devices (MUTCD) Interim Approval (IA-16), which allows the optional use of a bicycle signal face under certain conditions. These conditions are restrictive in the sense that they do not allow conflicting vehicular and cyclist movements, causing operational challenges for implementation in congested networks. UT-Austin conducted a before and after study under an approved Request for Experimentation (RTE) of the deployment of bicycle silhouette signal faces that allowed conflicting movements between cyclists and motorists. This study considered yielding compliance and red light compliance for a variety of permissive uses of the bicycle-specific signal face. Cyclist and vehicle red light running behavior was categorized as gap acceptance (waiting to find a gap during a solid red light); running the pedestrian light; signal jumping (anticipating the green light and entering the intersection during the all red phase); or other. The results show that overall red light compliance did not change in a significant way in the after scenarios. While vehicles did run red lights more often when there was an advanced green signal for cyclists, this was only observed to happen when no cyclists where present anywhere in the intersection. Yielding compliance was also categorized for both cyclists and motorists at the tested intersections. Not a single crash was observed during this study. In general, the results of these study show that the operational benefits gained from a permissive use of bicycle silhouette signal face do not sacrifice intersection safety.