History of APS in the U.S.
APS but no regulations
Although there are reports of audible pedestrian signals in the U.S. as early as 1920, they were not included in U.S. standards and regulations until MUTCD 2000.
- Common devices were bells or buzzers designed by engineers in response to a request from individuals who were blind.
- Earliest reported installations were near schools for the blind.
Figure 1-2. Pedhead-mounted APS; APS speaker mounted on top of pedestrian signal head
APS first mass marketed
Mid 1970's
- Cuckoo/cheep signals mounted on the pedestrian signal heads (pedhead-mounted APS), based on a Japanese system, were marketed in the U.S. These signals emitted sound from an overhead speaker only during the WALK interval and were typically aimed toward the opposite end of the crosswalk.
- Other types of devices developed in Europe and Australia (see Chapter 10, International Practice, Sweden and Australia) were not marketed in the U.S.
Controversy over their use
For early installations, there were complaints about noise of the signals from residents living near installations.
In addition, there was disagreement about the need for APS between two main consumer groups of blind people, American Council of the Blind and National Federation of the Blind. Until the early 1990's:
- American Council of the Blind (ACB) supported use of APS to provide additional information at all intersections.
- National Federation of the Blind (NFB) opposed all use of APS
While each of these consumer groups have a membership of approximately 25,000 people which combined represents less than 1% of people who are blind or who have low vision in the U.S., this disagreement was often very confusing to community officials. While the NFB has now stated that APS should be used in some situations, they are still opposed to "wholesale" installation at every intersection.
Problems with pedhead-mounted APS
See Appendix C for detailed information on research results.
Pedhead-mounted APS provide limited information:
- Two-sound system (cuckoo/cheep) does not provide unambiguous indication of WALK. Requires blind pedestrians to know their direction of travel at all times.
- Only provide sound during the WALK interval. While the signal sound is loud and intended to provide directional guidance across the street, the short duration of the WALK interval at most locations means that the sound ends before pedestrians complete their crossings
- No information about the presence or location of the pushbutton
Figure 1-3. Pushbutton-integrated APS
Newer types of APS available — Pushbutton-integrated
In the mid-1990's, APS that were integrated into the pushbutton, based on the European and Australian systems, began to be available in the U.S.
These APS provide audible indications from the pushbutton at a generally quiet volume, intended to be heard 6 to 12 feet from the pushbutton.
Additional features include
- Vibrotactile WALK indication, in addition to audible WALK indications
- Pushbutton locator tone which repeats constantly at once per second to provide information about the presence and location of a pushbutton
- Tactile arrow that points in the direction of travel on the crosswalk
- Automatic volume adjustment, so the APS responds to ambient sound and provides louder indications when the traffic is louder and quieter signals at times when traffic is quiet
Proper location is essential
The functioning of pushbutton-integrated APS is based on proximity to the crosswalk location. The closer the APS is located to the departure location, the quieter it can be. In addition, the vibrotactile indication and tactile arrow are not usable when located too far back from the street. Figure 1-4 illustrates installation recommendations.
Figure 1-4. Ideal Installation — Within 5 feet of the crosswalk extended, within 10 feet of the curb, and separated by more than 10 feet from other APS on the corner, adjacent to a level landing
Changes in intersection design, traffic and signalization
Changes in intersection design, traffic, and signalization have affected the ability of pedestrians who are blind to cross streets using traffic sounds, as discussed in detail in Chapter 2.
APS currently available in the U.S.
APS provide an auditory (tone or speech) indication of the WALK interval. Vibrotactile indication of the WALK interval is also required by the MUTCD , but not all APS devices available are capable of providing vibrotactile indications. Numerous other features are available and detailed descriptions of the various features can be found in Chapter 4.
In the previous version of this document (Accessible Pedestrian Signals: Synthesis and Guide to Best Practice), APS were described as one of four design types: pedhead-mounted, pushbutton-integrated, vibration-only, and receiver-based. These device design types were mainly categorized by the location and type of WALK indication provided, although there were characteristic differences in other features at that time. As technology has developed, several combinations of these different types have emerged, and modifications have been made that prevent easy separation of devices into four 'types'. The discussion of APS and their features using those terms becomes confusing. This Guide, proposed PROWAG (by incorporation of the MUTCD), and the MUTCD all recommend APS that have audible and vibrotactile WALK indications, which are only available when APS are integrated into the pushbutton. However, other features, such as additional beaconing speakers, may also be provided.
In this Guide, other than this chapter and Chapter 9, the labeling of types of APS has generally been dropped. These types are described here for clarification, as background information. Some manufacturers or distributors may continue to use these terms to describe available products.
Pushbutton-integrated
- Common in Europe and Australia and the required type in the US for new installations in the U.S.
- Speaker and vibrating surface located at the pushbutton
- A regularly repeating quiet locator tone provides information about the presence of the pushbutton and its location,(during the flashing and steady DONT WALK intervals).
- Pushbutton locator tone and WALK indication volumes respond to ambient sound
- Volume is typically adjusted to be heard only at the beginning of crosswalk
- May provide other information about the name of streets or the geometry of the intersection, or signalization
Pedhead-mounted
- Most common type installed between 1960 and 2000 in the U.S.
- Speaker mounted on top of the pedestrian signal head (pedhead)
- Bell, buzzer, cuckoo, cheep, tone, or verbal message during the WALK interval only
- Usually intended to be heard across the street and act as a beacon, thus are relatively loud
Receiver-based
- Message transmitted by infrared or LED technology from the pedestrian signal to a personal receiver held by the individual
- Blind pedestrians must have and use the appropriate receiver for the technology installed
- May provide other information about the name of streets, geometry of the intersection, direction of travel, and address information
Vibrotactile-only
- Arrow on the pushbutton housing or the pushbutton itself vibrates during the WALK interval
- Vibrotactile-only devices do not conform to the MUTCD 2009 requirements.
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