Signal Spotlight: Signalized Intersection Design with Accessibility in Mind
October is National Pedestrian Safety Month, so this month’s Signal Spotlight focuses on accommodating pedestrians at signalized intersections. According to the National Highway Traffic Safety Administration (NHTSA), 26% of pedestrian deaths in the United States occur at intersections. That represents 1,667 pedestrians killed each year. In Connecticut, the overall number of pedestrian-related crashes decreased from 1,574 in 2019 to 1,141 in 2020, but pedestrian-related crashes involving a fatality increased from 53 in 2019 to 60 in 2020. Designing the physical environment at signalized intersections to accommodate pedestrians of all ages and abilities, in combination with timing tools like the leading pedestrian interval, can increase safety for these vulnerable road users.
The Draft Public Rights of Way Accessibility Guidelines (PROWAG) outlines design practices to accommodate pedestrians with disabilities within public rights of way. Intersections that are designed with these users in mind will typically accommodate pedestrians of all abilities sufficiently. The PROWAG discusses several considerations specific to signalized intersections that designers and operators of traffic signals should keep in mind.
The first item to consider is pedestrian indications. All new installations should include countdown indications mounted between seven feet and ten feet above the ground. Where visual pedestrian signals are provided, audible pedestrian signals (APS) should also be provided for pedestrians who have low vision. Information on the required features of APS, including audible tones, tactile feedback and speech messages may be found in Section 4E.09 of the Manual of Uniform Traffic Control Devices (MUTCD).
The next consideration is the pedestrian access route (PAR). A minimum of four feet should be provided around obstructions, including pedestrian push buttons, mast arm and span pole bases, and sign posts. The pedestrian access route, including the sidewalks, ramps, and landing areas, should have a maximum slope of five percent and a maximum cross slope of two percent. It’s important to remember that the PAR does not end at the sidewalk ramp and the same standards should be applied through the crosswalks.
Push Button Locations are also a concern when accommodating pedestrians. When two push buttons are located at the same corner, they should be at least ten feet apart. If that’s not possible, it is important to provide a way for pedestrians with low vision to distinguish between the two buttons. This can be accomplished using a locator tone, a tactile arrow showing the direction of the crossing associated with the button, and an audible message denoting which of the two street crossings the button is provided for.
To ensure pedestrians using wheelchairs are accommodated, it is important to place push buttons within reach. As illustrated in the diagrams below from the PROWAG, the buttons should be mounted between 42 ” and 48 ” above the ground and the maximum reach necessary to press the button should be ten inches.
When considering location, the push button should be placed next to an accessible landing area to provide a stable space for the wheelchair while a pedestrian pushes the button. Keep in mind that guide rail, fences, bushes and other obstructions make it difficult for those using wheelchairs to reach a push button. To allow time for travel between the button and the sidewalk ramp, the push button should ideally be placed within five feet of the curb or edge of pavement and should not be placed more than ten feet away.
An accessible route may look acceptable on the construction plans, but often changes are made to a design to address field conditions. Installers and inspectors can ensure accessibility at the intersection by double checking the location of pedestrian signal equipment. Here is a checklist with some items to consider:
Are the push buttons and APS units close to the crosswalks they control?
Are the push buttons at the correct height?
Are the tactile arrows aligned with the crosswalks they control?
Are the audible indications functioning and do they make sense?
Are the audible locator tones and walk messages at the appropriate volume?
For more information on accessibility, visit the U.S. Access Board website at https://www.access-board.gov/prowag/. Information on Leading Pedestrian Interval and other proven safety countermeasures may be found on the Federal Highway Administration’s website at https://safety.fhwa.dot.gov/provencountermeasures/.
If you have traffic signal systems questions, please contact:
Theresa Schwartz, P.E., P.T.O.E. – Traffic Signal Circuit Rider