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close windowSeattle, Washington
Peter Lagerwey, Pedestrian & Bicycle Program Coordinator, City of Seattle
Bicyclists using residential streets often have trouble crossing arterial streets at unsignalized intersections. This is especially true for bicyclists trying to cross high-volume, multi-lane arterial streets.
Where streets are laid out in a traditional grid pattern, residential streets become particularly attractive to inexperienced bicyclists. However, if crossing major arterials results in too much delay or makes the crossing too difficult, inexperienced bicyclists who are not comfortable using arterial streets will be discouraged from bicycling.
Seattle’s solution has been to install pedestrian or bicycle crosswalk signals (formally called half-signals). A crosswalk signal is a pedestrian- or bicyclist-actuated light that stops arterial traffic only, leaving the lower-volume cross-street unsignalized. It allows bicyclists and pedestrians to cross safely upon demand without unnecessarily creating delays for arterial street traffic that a fully signalized intersection might impose. It also can prevent cut-through motor vehicle traffic on the residential street that can happen with the installation of a full signal.
Crosswalk signals also have been successfully installed to facilitate “bicycle boulevards” in various communities around the country. These are bike routes that are designed to encourage fast, through bicycle traffic on residential streets while discouraging through motor vehicle traffic. The crosswalk signals are combined with other treatments such as diverters (for motorists) to create the bicycle boulevard. More often, these signals also have been installed to facilitate pedestrian crossing near schools, hospitals and in neighborhood shopping districts. To date, more than 80 crosswalk signals have been installed in Seattle.
It is relatively easy to evaluate the success of a pedestrian half-signal. If the number of crashes and bicycle and pedestrian complaints goes down, then it’s a success. In Seattle, half-signals have consistently had crash rates equal to or lower than full signals. If the arterial has high volumes, traffic impacts such as the frequency of motorist delays should be studied. If frequent red phases cause delays, consider lengthening the green phase a bit. To strike the right balance, observe the intersection throughout the day and, if necessary, vary the timing.
Seattle’s crosswalk signals have been well received. In most ways, they operate like the midblock signals that are used in many communities. If installed with the same care that midblock signals are installed, they can be effective and safe. When Seattle’s crosswalk signals are reviewed by other communities, their traffic engineers often express concerns about possible driver confusion which in turn could lead to increased crashes. This has not been Seattle’s experience — they don’t increase crash rates, people like them, and there is constant demand to have them installed at new locations.
Most jurisdictions use the Manual on Uniform Traffic Control Devices (MUTCD) to determine signal warrants, whether the signals are to be installed for vehicular traffic or pedestrians. Crosswalk signals, however, have not yet been incorporated into the MUTCD. Consequently, it is necessary to create more flexible guidelines for installing a crosswalk signal instead of a full signal when there are insufficient gaps for bicyclists and pedestrians. We have two suggestions for installing a crosswalk signal: 1) when traffic volumes on the intersecting street are less than 50 percent of MUTCD recommended benchmarks for a full traffic signal; and 2) when a substantial amount of motor vehicle traffic might be induced to opt for and use a lower volume, residential street if a full signal were installed.
Cost depends on a lot of factors, including the location of the nearest power source, the type of poles installed and the availability of space for signal equipment. However, in general a crosswalk signal is about half the cost of a full signal. In many cases, they can be installed for less than $30,000.
Loren Raynes
Signal Operations
Seattle Department of Transportation
700 5th Avenue, Suite 3900
P.O. Box 34996
Seattle, WA 98124-4996
(206) 684-5119
Joe Couples
Signal Operations
Seattle Department of Transportation
700 5th Avenue, Suite 3900
P.O. Box 34996
Seattle, WA 98124-4996
(206) 684-5246
Peter Lagerwey
Bicycle & Pedestrian Program Coordinator
Seattle Department of Transportation
700 Fifth Avenue, Suite 3768
P.O. Box 34996
Seattle, WA 98124-4996
(206) 684-5108
The modification (half signals) 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 half signals (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.