Bike boxes and lanes may increase “right hook” crashes in some circumstances

By Bill Holloway

Portland, Oregon, has been recognized throughout the U.S. for its efforts to both promote bicycling and retrofit its street network to be safer for and more appealing to bicyclists. But a new Portland Bureau of Transportation report seems to indicate that the new designs may be giving bicyclists a little too much comfort on downhill runs approaching intersections.

A preliminary analysis of bike crashes at intersections in Portland with painted bike lanes, bike boxes, and bicycle-related signage has indicated that, in some circumstances, bicycle lanes may actually increase the number of bicycle/motor-vehicle crashes. While bicycle boxes appear to be accomplishing the goal of reducing right hook crashes at the start of a green signal, bicycle lanes at intersections may increase the risk of right-hook crashes during “stale” green signals – those that have been green for some time – at some intersections, particularly those at the bottom of hills.

The researchers found that most motorists (98 percent) yielded to bicyclists overtaking on their right, indicating that drivers generally understand their responsibility to yield to cyclists when making right turns. However, at intersections on hills where bicycles are often traveling at a high rate of speed, drivers may be unable to see bicyclists overtaking on their right prior to turning.

The final report by Dr. Christopher Monsere, Portland State University, will be released in early 2013 but potential design concepts being considered to reduce the incidence of right-hook crashes include:

  • Redesigning intersections to include separate right-turn lanes by removing a through-travel lane or parking;
  • Prohibiting all vehicle right turns;
  • Providing a signal phase for the through movement of bicycles exclusive of right-turn vehicle conflicts; and
  • Providing an active warning/regulatory sign that is activated by approaching bicycles to warn drivers of potential conflicts.

Bill Holloway is a Transportation Policy Analyst at SSTI.