Accessible Pedestrian Signals

Description

The U.S. Department of Transportation Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD) defines an Accessible Pedestrian Signal (APS) as “a device that communicates information about pedestrian timing in nonvisual format such as audible tones, verbal messages, and/or vibrating surfaces” (MUTCD, 2003, Section 4A.01). Accessible pedestrian signals are fundamental in designing accessible rights-of-way [link to article on this site].

Importance

Changes in street and sidewalk design, especially intersection design and signalization, and quieter cars make it more difficult for blind and visually impaired pedestrians to use traditional street crossing techniques. Accessible pedestrian signals, or APS, provide audible and/or vibrotactile forms of information that allow people with diminished visual ability to cross streets and intersections safely. People without visual disabilities benefit from having an audible reminder of when it’s safe to cross.

Guidelines

The National Cooperative Highway Research Program (NCHRP) undertook development of guidelines for accessible pedestrian signals in 1998, producing a synthesis and guide to best practices, Accessible Pedestrian Signals: Synthesis and Guide to Best Practice, in 2003. The NCHRP announced an update in 2008; Accessible Pedestrian Signals: A Guide to Best Practice, which can be downloaded and printed. Accessible pedestrian signal guidelines were developed by the University of North Carolina Highway Safety Research Center (HSRC) and Accessible Design for the Blind. The NCHRP promises further updates as new technologies are developed or technologies long used in other countries are adopted in the US.

While there are four types of APS currently available in the US, draft Public Rights-of-Way Accessibility Guidelines require pushbutton-integrated APS providing an audible and vibrotactile WALK signal. Although these guidelines have not been finalized as standards, they are currently considered best practice. The other three types of APS described below are also in use. For a summary and aid to selection of devices and manufacturers, go to Walking Info.org.

Pushbutton-Integrated

Common in Europe and Australia, pushbutton-integrated APS devices recommended by the Access Board provide a speaker and a vibrating surface or arrow at the pedestrian button. All sounds come from the pedestrian pushbutton housing, rather than the pedhead (see below). A quiet pushbutton locator tone, repeating once per second during the flashing and steady don’t walk intervals, provides information to the blind individual about the presence and location of a pedestrian pushbutton. APS include a tactile arrow, which should be aligned with the direction of travel on the crosswalk the APS controls/signals. The walk interval may be signaled by the same tone as the locator tone, at a faster repetition rate, by another tone at a faster repetition rate, or by a speech message. The recommended tone cannot be easily confused with other sounds such as vehicle back-up warnings or birdcalls.

All currently available pushbutton-integrated APS automatically adjust in response to ambient sound levels. The pushbutton locator tones and walk indications should be adjusted to be audible 2 to 4 meters (6 to 12 feet) from the pole or from the building line, whichever is less. These signals are intended to be loud enough to be heard ONLY at the beginning of the crosswalk, but on some APS, increased volume can be actuated if pedestrians press the pushbutton for one second or longer. Manufacturers: Campbell, Novax, Panich, Polara, and Prisma.

Pedhead-Mounted

This type of APS has a speaker on top or inside of the pedestrian signal head and provides a bell, buzzer, cheep, cuckoo, speech message, or some other audible tone during the walk interval of the pedestrian signal. Some models respond to ambient sound, becoming louder when the traffic noises are louder and quieter when the traffic is quiet. They are usually intended to be heard across the street and act as a beacon, and are relatively loud. However, surveys of pedestrians who are blind and recent research indicate that this type of beaconing does not help and may prevent pedestrians who are blind from hearing vehicles and other important information. Draft PROWAG does not recommend pedhead-mounted devices because they do not provide vibrotactile information. Manufacturers: Mallory, Novax, US Traffic, Wilcox

Vibrotactile-Only

This type provides only vibration at the pedestrian pushbutton. The arrow or button vibrates when the walk signal is on. It must be installed very precisely next to the crosswalk to be of value, and the person who is blind or visually impaired must know where to look for it. Draft PROWAG does not recommend vibrotactile-only devices because they do not provide audible information. Manufacturers: Campbell

Receiver-Based

A message is transmitted by infrared or LED technology from the pedhead to a personal individual receiver. The person who is blind or visually impaired has a receiver and points it at the pedhead to receive the message. Draft PROWAG did not recommend receiver-based devices because the information is not available to those who don’t have a receiver. Manufacturers: Talking Signs (combined with Polara APS)

APS Installation Recommendations

Installation in the proper location and orientation in relation to the crosswalk is important for APS use, particularly for devices integrated into the pushbutton. Recent research, Draft PROWAG, and MUTCD all recommend that each APS device should be on a separate pole, located as close as possible to the curb line and to the crosswalk line furthest from the center of the intersection. APS pushbuttons must be adjacent to a level landing and mounted at 42” above the sidewalk surface. In addition, devices should have a pushbutton locator tone, a vibrotactile walk indication, and a tactile arrow oriented parallel to the direction of travel on the associated crosswalk. Braille street name information on the APS is also desirable. Draft PROWAG requires that the name of the street to be crossed is accessible to pedestrians who are blind.

Two APS on a corner should be at least 10 feet apart in order for pedestrians to easily distinguish which device is sounding. Both APS should have the same WALK indication; the location clarifies which crosswalk the APS is signaling. The recommended WALK indication for APS that are located according to these recommendations is a rapid tick, or percussive sound, at 10 repetitions per second.

Where it is technically infeasible to install two APS pushbuttons (and speakers) on a corner on two separate poles at least 10 feet apart, it is recommended that verbal WALK messages following the model “Beechwood; walk sign is on to cross Beechwood” be used. If speech messages are used, it’s essential that the pedestrian know the name of the street being crossed. An additional feature, a pushbutton information message, is needed on the device to provide street name information to the pedestrian who is unfamiliar with the intersection. This feature provides the name of the street controlled by the pushbutton when pushed and held during the flashing or steady don’t walk interval.

Research and Development Needs

Research continues on other types of APS, including devices used in other countries. Walking Info.org stays abreast of developments, and plans to update its website for the new version of Accessible Pedestrian Signals: A Guide to Best Practice by the end of 2008.

Links

The APS guide is an interim product for NCHRP Project 3-62. The print version of the guide was prepared by J.M. Barlow, B.L. Bentzen , Lee Tabor of Accessible Design for the Blind. WalkingInfo.org is a project of the Pedestrian and Bicycle Information Center.

Author

This article was synthesized from the Transportation Research Board’s National Cooperative Highway Research Program publication, developed by the University of North Carolina Highway Safety Research Center (HSRC) and Accessible Design for the Blind. This article was compiled from various sources by Susan S. Hunter, Ph.D.

References

Accessible rights-of-way [link to article on this site], on this website, provides information and references for other aspects of making public rights of way accessible for people with disabilities.

American Access Board publication Interfacing Audible Pedestrian Signals and Traffic Signal Controllers provides detailed specifications visual and tactile signs including directional, informational, and warning signs.