A multi-year study of bike-involved collisions at Portland intersections that have bike boxes has returned mixed results showing only minimal reductions in collisions at some intersections and increases at others. The results have prompted the city to rethink some of the design elements around bike boxes particularly when they are in the downhill direction.
The bike boxes have essentially fixed the problem of right hook collisions when signals turn from red to green, but they have done little and perhaps made worse the problem of right hooks on a “stale green,” meaning a light that has been green for a while.
Of the 11 intersections where bike boxes were installed in 2008, seven saw a very small decrease in the number of collisions, but four saw dramatic increases. A common factor in those instances is that the bike boxes are located on a downhill, which means faster bikes and, therefore, an increased chance that turning vehicles will not yield (AKA “I didn’t see him/her”).
While the law is clear that it is the responsibility of people driving to yield to people on bikes before turning, intersections with higher-than-usual instances of failure to yield behavior points to road design failures. Bike Portland outlines the city’s analysis of the results:
This surprising increase in right-hooks led PBOT to take a closer look at what is happening at these four locations. From reading police reports they found that 88% (a “high proportion”) of the collisions occurred during a “stale” green signal. Or in other words, the collisions occurred when the light had been green for some time and not during the red phase or right as the light turns green. After observing the locations, PBOT also determined other similarities in the behavior of road users that they feel are directly contributing to the collisions:
- All three locations have downhill grades on the treatment approach.
- The 85% speed for cyclists observed overtaking right-turning vehicles was approximately 18 mph, which we find to be fast speed for the condition.
- A high percentage of cyclists were overtaking right-turning vehicles during the peak-hour observation periods.
- A very high percentage of vehicles (98%) yield to cyclists over-taking on their right.
The options Portland has come up with to address these issues range from signage to better instruct drivers to yield (including bike-activated beacon lights on signs), signage to try to get people on bikes to slow down, restricting right turns entirely at key intersections, installing separate signal phases for people on bikes, and installing separate right turn lanes to the right of bike lanes.
Of course, safety from right hook collisions is not the only purpose of bike boxes. They can create new mobility options for people on bikes, allowing people to make “two-stage” left turns by entering a bike box and waiting for the signal to turn green instead of trying to merge all the way to the left lane to turn (the best example of this working successfully in Seattle is at N 34th and Fremont). This is a critical function that allows designs like the upcoming two-way cycle track on Broadway to work.
When bike boxes are installed in a way that restricts right turns on red (like at 12th and Pine on Capitol Hill), they can also increase safety for people on foot. In most of Europe, right turns on red are always restricted by default for this reason. But since Gerald Ford instated them, the U.S. has grown used to the privilege, though talk of banning them persists. In a way, bike boxes reinstate this rule targeted intersection by targeted intersection.
From what I can tell, Seattle does not have any real downhill bike boxes (please correct me if I’m wrong). One of the bike trapezoids on Madison is on a downhill, but there is no bike lane so it does not seem to be a comparable facility to those discussed in the Portland study.
Avoiding right hooks is one of the main arguments “vehicular” cyclists make against bike lanes. After all, if you are just in line behind the turning car, there is little chance you will be right hooked. This is, indeed, the solution SDOT goes with most often: Drop the bike lane the block before an intersection and have people biking merge with the right general traffic lane.
However, since most people do not feel comfortable biking in traffic, a truly safe and separated solution for intersections is a must for urban cycling to move to the next stage of popularity. It seems just painting a bike box is not enough for every intersection, and best practices will probably come with more financial and political burdens.
For example, we need to stop designing our intersections for the minority of vehicles that require wide turn radii. Sharper right turn angles slow turning vehicles, thus increasing safety for people on foot and bike. But many U.S. design standards force engineers to design all our roads to accommodate large trucks (even if they are not along major trucking or articulated bus routes), which is a big impediment to designing intersections the truly safe Dutch way:
Designing safe bike facilities on hilly terrain is relatively uncharted territory, but that means Seattle and Portland need to lead the way. The majority of collisions involving people on bikes occurs at intersections, and the city’s current strategy of simply dropping the bike lane before intersections cannot continue if we want to attract the majority of people who do not feel comfortable biking mixed with heavy traffic.