Active Warning Analysis for ‘Right Hook’ Conflicts


Lancaster Engineering worked with the City of Portland to perform an in-depth analysis of video footage and historical crash data at two intersections within Portland that are prone to ‘right hook’ conflicts between people biking and driving. Though the intersections had bike boxes in place, serious crashes involving vulnerable roadway users continued to occur, particularly at the intersection of NE Couch Street at NE Grand Avenue. At that intersection an active warning sign was installed which utilizes intelligent signal timing logic to display only when 1) there is a person biking along the bike lane in advance of their respective signal, and 2) when the associated signal phase would display green and allow for the opportunity of a right-hook conflict to occur. Following a fatal right-hook bike/car crash at the intersection of SW Madison Street at SW 3rd Avenue, this type of safety treatment was considered for that intersection and Lancaster Engineering analyzed the observed conflicts and historical crash data  at this particular intersection.

Lancaster Engineering explored the differences and similarities between the two study intersections and how that could relate to the initial results suggesting the active warning sign in operation at the intersection of NE Couch Street at NE Grand Avenue is effective in reducing the chance for a right-hook conflict to occur. Based on our experiences with the study we also provided guidance for future research related to this type of active warning sign.