About Accessible Pedestrian Signals

San Francisco APS agreement

The blind community and the city of San Francisco signed a historic agreement on APS in 2007. The City committed to install APS at 80 intersections and to spend 1.6 million dollars installing APS. As of March, 2009, the work has been done on approximately 70 intersections and over 650 APS units have been installed. The city is following technical specifications negotiated as part of the agreement.

The following resources are available on Lainey Feingold's website:
San Francisco APS Technical Specifications
San Francisco full APS agreement
Press release announcing the San Francisco Agreement
AccessWorld Article on San Francisco Agreement

Report on APS:

New report published by NCHRP in 2008: Accessible Pedestrian Signals: A Guide to Best Practice. NCHRP Web-Only Document 117A.

Accessible Pedestrian Signals: A Guide to Best Practice is available in html format at www.apsguide.org.

The Access Board has published a new report on Common Problems Arising in the Installation of Accessible Pedestrian Signals.

What is an Accessible Pedestrian Signal?

The Manual on Uniform Traffic Control Devices (MUTCD) defines an Accessible Pedestrian Signal as “a device that communicates information about pedestrian timing in nonvisual format such as audible tones, verbal messages, and/or vibrating surfaces.” (Manual on Uniform Traffic Control Devices 2003, Section 4A.01)

Why are they needed?

Changes in intersection design and signalization, as well as the presence of quiet cars, have affected the traditional street crossing techniques used by pedestrians who are blind or visually impaired, making the pedestrian phase harder to recognize without seeing the visual pedestrian signal. APS provide the same information that is provided by the visual pedestrian signal in an audible and/or vibrotactile format, providing access to the pedestrian signals for pedestrians who are blind.

Best Practice for Accessible Pedestrian Signals

There are four types of APS currently available in the US, however Draft Public Rights-of-Way Accessibility Guidelines (Draft PROWAG), published in June 2002 and updated in November 2005, require pushbutton-integrated APS that provide an audible and vibrotactile indication of the WALK signal. While the guidelines have not been finalized as standards, these draft guidelines should be considered best practice at this time (Federal Highway Administration memo on public rights-of-way, January 2006). The other three types of APS are also described below for your information.

Types of Accessible Pedestrian Signals

Pushbutton-integrated

Pushbutton-Integrated APS Pushbutton-integrated devices have been common in Europe and Australia for years and are the type of APS recommended by the Access Board in the Draft PROWAG. They provide a speaker and a vibrating surface or arrow at the pedestrian button, and all sounds come from the pedestrian pushbutton housing, rather than the pedhead. 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 indicated 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 is not confusable with other sounds such as vehicle back-up warnings or birdcalls.

All APS currently available of this type 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, Prisma

Pedhead-mounted

APS mounted on the top of the pedhead This type of APS has a speaker on top of or inside 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 as a consequence. 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

Vibrotactile Unit 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

Hand held infrared receiver 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)

Accessible Pedestrian Signals: Installation recommendations

Installation in the proper location and orientation in relation to the crosswalk is important for the use of APS, particularly for device 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 as close as possible to the crosswalk line that is furthest from the Ideal Placement for Accessible Pedestrian Signals 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.