William W. Hunter, Senior Research Scientist, UNC Highway Safety Research Center
Bike box is a term that has gained popularity in the United States for a European treatment usually known as the advanced stop bar (figure 1). The box is a right angle extension to a bike lane at the head of the intersection. The box allows bicyclists to get to the head of the traffic queue on a red traffic signal indication and then proceed first when the traffic signal changes to green. Such a movement is beneficial to bicyclists and eliminates conflicts when, for example, there are many right-turning motor vehicles next to a right side bike lane. Being in the box, and thus at the front of the traffic queue, also tends to make bicyclists more visible to motorists.
Figure 1. Diagram of a bike box used with left side bike lane.
A bike box and accompanying traffic signs, but with no special traffic signals to hold motorists or direct bicyclists to the box, were installed on High Street at 7th Avenue in Eugene, OR, in the summer of 1998. The application of the bike box was innovative in the sense that the intent was to give bicyclists a safer way to change from one side of the street to the other at a busy downtown intersection featuring two one-way streets. Prior to the box, the vast majority of cyclists approached on High Street in the left-side bike lane adjacent to parked motor vehicles. The bike lane was left-side to match with another one-way couplet and to avoid having a right-side bike lane next to intersections with double right-turn lanes. Many of the cyclists approaching in the left-side bike lane preferred to switch to the right-side (through) bike lane on the far side of the intersection because at the next block cyclists in the left-side bike lane must turn left. Moving from left to right side after the intersection entails crossing three lanes of traffic. The average annual daily traffic on High Street is about 8,500 vehicles per day, and the peak hour total is about 1,000 motor vehicles. When traffic was busy, bicyclists could have difficulty finding a gap large enough to allow an easy move from left to right. Some bicyclists were aggressive and used hand signals to indicate their movement from left to right. Many, however, simply stopped in the bike lane and waited for a suitable gap.
Besides the crossover from left to right after the intersection identified above, there were a variety of other ways used by bicyclists to negotiate this intersection. Some would shift from the bike lane to the motor vehicle traffic lanes prior to the intersection. Others rode or walked their bicycle through the crosswalks on both High Street and 7th Avenue as pedestrians would, a movement that delays right-turning motorists. Some bicyclists would intentionally disobey the traffic signal at the intersection proper while motorists waited for the signal to change, move into the intersection, and then shift from left to right.
With the bike box in place, bicyclists desiring to change from the left to the right side of High Street can proceed to the head of the traffic queue on a red traffic signal indication and then cross over to the front of the second lane of traffic (figure 2). The second lane is a combination through/right-turn lane. The right-most lane is right turn only. Right turn on red is not permitted; however, some motorists do not comply. The box is not meant to be used on a green traffic signal indication.
Bicyclists have the right of way when in the box. They generally are able to accelerate quickly through the intersection ahead of motor vehicles when the signal changes to green, then safely switch to the through bike lane on the right-hand side of High Street such that motorists are not inconvenienced.
Several other steps were taken to help bicyclists and motorists understand the use of this innovative treatment at this intersection. A press release was prepared and stories run in the local newspaper and the University of Oregon student newspaper. A special sign board with information about how to use the bike box was placed on a construction barricade near the intersection pedestrian crosswalk. The barricade with educational sign also had a flashing light attached. Traffic signs with orange diamond attachments added for conspicuity were placed at the intersection to indicate that traffic, except bikes, should stop prior to the box on a red signal indication (STOP HERE ON RED, with EXCEPT BICYCLES mounted below). A yellow diagrammatic sign with a BICYCLES MERGING message was already in place.
Figure 2. Three bicyclists using the box correctly.
Cyclists traveling through the intersection were videotaped before and after placement of the box. The videotapes were coded to evaluate operational behaviors and conflicts with motorists, other bicyclists, and pedestrians. Other data concerning bicyclists’ characteristics and experience, as well as their opinion of how the bike box functioned, were obtained through short oral surveys. These surveys were performed on days when videotaping was not occuring.
The use of a bike box to facilitate the movement of bicyclists from a left-side bike lane, through an intersection, and across several lanes of a one-way street to a right-side bike lane was an innovative approach. The data indicated that the use of the box was reasonably good. Usage can be examined several ways.
A problem with motor vehicle encroachments into the box likely diminished the amount of use. Overall, encroachments occurred in 52 percent of the red traffic signal indications after the box had been in place for five months. While this is not uncommon, even in Europe where the design has been in place for some time, it is troubling, and remedies should be sought. Bicyclists surveyed about the pilot location tended to frequently complain about the encroachment problem.
The bike box had no effect on signal violations. Some 6 to 7 percent of bicyclists violated a red signal indication both before and after placement of the box.
The rate of conflicts between bicycles and motor vehicles changed little in the before and after periods. The rate was 1.3 conflicts per 100 entering bicyclists before the bike box and 1.5 conflicts per 100 entering bicyclists after. However, the pattern of the conflicts did change. Eight of the 10 conflicts in the before period involved a bicyclist moving from left to right across the travel lanes after the intersection. Two of the 10 conflicts in the after period were of this type. Six of the after conflicts took place within the intersection proper, but three of these involved bicyclists coming off the right sidewalk and conflicting with right turning motor vehicles. No conflicts took place while using the bike box in the normal sense.
Use of the bike box to help bicyclists negotiate a difficult maneuver at this intersection was considered to be a rigorous test. All things considered, the innovative treatment worked reasonably well. More evaluations should be conducted in other settings and for other maneuvers to further understand how well this design works in the United States and how it might be improved. For upcoming evaluations, a number of recommendations can be made.
In summary, the bike box is a promising tool to help bicyclists and motorists avoid conflicts in certain kinds of intersection movements. More boxes need to be installed and evaluated to further understand their effectiveness in different settings. Pilot testing the Danish treatment of recessed stop bars for motor vehicles is also recommended.
Costs included paint (regular, not thermoplastic) removal, new thermoplastic, two signs near intersection and informational sign for approximately $2,500 parts and labor. If traffic loops have to be moved: $1,000/lane extra.
Bicycle & Pedestrian Program Coordinator
City of Eugene Public Works
858 Pearl Street
Eugene, OR 97401
(541) 682-5471 (voice)
(541) 682-5598 (fax)
UNC Highway Safety Research Center
730 Martin Luther King Jr Blvd, Suite 300
Chapel Hill, NC 27599-3430
The modification (bike box) that is the subject of this case study is not compliant with the Manual on Uniform Traffic Control Devices, nor is it currently being considered for inclusion. Accordingly, it is imperative that any jurisdiction wishing to utilize the bike box (or any other non-approved traffic control device) should seek experimental approval from the Federal Highway Administration. For information on how to do so, please visit this Web site: http://mutcd.fhwa.dot.gov/ kno-amend.htm.