WALK indication

Criteria for WALK indications

WALK indication is critical

The WALK indication provides critical safety information. The WALK indication should be:

Criteria

 

Careful APS location is essential

MUTCD 2009 and Proposed PROWAG (by reference) require APS to be located at the pushbutton (pushbutton-integrated) to enable use of the vibrotactile feature. Discussion in this chapter assumes that APS are integrated into the pushbutton, unless another mounting location is specifically discussed.

There are a number of APS available that meet the above listed criteria, however proper installation is also critical to their effective functioning. Chapter 6 discusses installation location requirements in detail.

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Current recommendations for WALK indications

Audible and vibrotactile indications required

Audible (speech or tone) and vibrotactile indications of the WALK interval are required by the 2009 MUTCD .

WALK indications can be provided by use of

More information about the use of each is provided on the following pages.

Recent research recommends tones at locations where the speakers for APS for two different directions can be separated. Speech messages are recommended where speakers must be located on the same pole or less than 10 feet apart.

Associating tones with direction of travel

In the past in the United States, audible pedestrian signals have utilized two different tones that are associated with two different crossing directions broadcast from speakers mounted at the pedestrian signal head. The most common tones used were the bird sounds, specifically "cuckoo" and "cheep", with the cuckoo used for north/south crosswalks, and the cheep for east/west crosswalks. However, research since 1988 has documented that such a system is often ambiguous and confusing (see Appendix C).

Using a different tone for each direction of travel is no longer recommended in the U.S.

Use of a single tone for crossings in all directions

In Europe and Australia, a single tone has been used successfully for years to indicate the WALK interval from speakers located at the pedestrian pushbutton. There is some variability in the tones used. Typically, the tone for WALK is the same tone as the pushbutton locator tone, repeated at a faster repetition rate, usually about 10 times faster. The same tone is used for all crossing directions.

A single tone works because the standardized location of the pushbutton-integrated speaker in relation to the crosswalk provides information about which crosswalk has the WALK interval. Pedestrians are beside the appropriate APS when they are waiting to cross, normally within arm's reach of the APS, and at some distance from the APS for another crosswalk. Speakers located in this manner are now included in the 2009 MUTCD .

See the Chapter 6 discussion of installation decisions for more about location of APS speakers and vibrotactile WALK indications.

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WALK indication — tones

Locator tone plus rapid tick walk indication

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Description

A tone is provided during the WALK interval. The WALK indication of APS in the US has typically been provided by an audible signal such as a beep, buzz, percussive sound, or cuckoo/cheep. Current recommendations are that the tone used to indicate the WALK interval should be a ticking tone which repeats 8 to 10 times per second, otherwise known as a rapid tick. That tone is provided from the pedestrian pushbutton location.

Additional Information

The rapidly repeating tick tone (at least 8 times per second) has been found to result in faster response than verbal messages or a two-tone system (cuckoo/rapid tick). Errors in responding to the correct signal were also reduced by using the rapid tick tone, when two APS on a corner were separated by at least 10 feet and each was located close to the crosswalk it signaled. For information about the research on tones, see Appendix C.

The WALK indication should also have a faster repetition rate than the pushbutton locator tone; MUTCD specifies the repetition rate and duration of the pushbutton locator tone at once per second (see pushbutton locator tone).

Tones consisting of multiple frequencies, high and low, with a large component at 880 Hz have been found to be highly detectable and localizable in the presence of traffic sound. Frequencies above 1kHz are difficult for persons with age related upper-frequency hearing loss to detect. However for persons with normal hearing, the presence of multiple higher harmonics aids localization.

When to use

An audible WALK indication is needed on any APS.

Tone indications should be used where speakers are separated by adequate distance and located close to the crosswalk they serve, so it is clear which speaker is sounding. Tone indications should be provided from pushbutton-integrated speakers, rather than from speakers mounted on pedestrian signal heads.

References

Currently the MUTCD states: “Where two accessible pedestrian signals are separated by a distance of at least 10 feet, the audible walk indication shall be a percussive tone. Where two accessible pedestrian signals on one corner are not separated by a distance of at least 10 feet, the audible walk indication shall be a speech walk message. Audible tone walk indications shall repeat at eight to ten ticks per second. Audible tones used as walk indications shall consist of multiple frequencies with a dominant component at 880 Hz.” (Section 4E.11, P7 & P8)

Research has been completed on detectability and localizability of tones and use of two different tones versus a single tone. See Appendix C for more information.

How used by pedestrians who are blind or who have low vision

The audible WALK indication provides a clear cue to the beginning of the pedestrian phase. Pedestrians will evaluate traffic and the intersection, then listen for the WALK indication. After hearing the WALK indication, they typically check that traffic has stopped and no cars are turning across their path before beginning their crossing.

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WALK indication — speech messages

Locator tone plus speech walk indication

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Description

A speech message is provided during the WALK interval, usually from a speaker located at the pushbutton.

The message is required to follow the recommended model: "Maple, WALK sign is on to cross Maple." The recommended speech message for an intersection with an exclusive pedestrian phase is "WALK sign is on for all crossings." (MUTCD Section 4E.11, P18 & P19)

Additional Information

The speech WALK message must be detectable, localizable, recognizable, and must also be correctly understood by all users. Speech messages from pushbutton-integrated APS seem very user-friendly and have become popular in the U.S. market. However, the words and their meaning must be correctly understood by all users in the context of the street environment where they are used.

Use of speech messages will not automatically solve all ambiguity problems. In even moderate traffic conditions people who have age-related or other hearing losses, people who are not native English speakers, and people with cognitive disabilities are likely to miss hearing or to misunderstand some words, possibly resulting in misunderstanding entire messages.

Model messages have been determined through research (see Appendix C). Recommendations for word order and wording of the model messages should be strictly followed. Where complete sentences are used in the models, they should be used in actual messages for the same situations. In the model messages, such words as street, avenue and road are not used, however in some locations, they may be needed to avoid ambiguity.

Pedestrians have to know the names of streets they are crossing in order for speech WALK messages to be unambiguous. In getting directions to travel to a new location, blind and low vision individuals do not always get the name of each street to be crossed. They may only know that they have to cross four streets before looking for their destination. Therefore, the APS has to give the user the name of the street controlled by the pushbutton. This can be done by means of a pushbutton information message during the flashing or steady DONT WALK intervals. See Chapter 4 for a description of pushbutton information messages and recommended message wording.

The user must then combine the information from the pushbutton information message or Braille label, the tactile arrow, and the speech WALK message in order to correctly respond to the speech WALK message. Information from all may be necessary to correctly identify the street and crossing interval at an unfamiliar intersection. This complex process is much more cognitively demanding, and more liable to result in errors or delay than the use of a tone from a speaker located right beside the crosswalk.

When to use

An audible WALK indication is needed on any APS. Speech WALK messages are recommended only where pushbutton speakers must be located on the same pole, or less than 10 feet apart.

References

MUTCD 2009 states that: " 17 If speech walk messages are used to communicate the walk interval, they shall provide a clear message that the walk interval is in effect, as well as to which crossing it applies. Speech walk messages shall be used only at intersections where it is technically infeasible to install two accessible pedestrian signals at one corner separated by a distance of at least 10 feet.

18 Speech walk messages that are used at intersections having pedestrian phasing that is concurrent with vehicular phasing shall be patterned after the model: “Broadway. Walk sign is on to cross Broadway.”

19 Speech walk messages that are used at intersections having exclusive pedestrian phasing shall be patterned after the model: “Walk sign is on for all crossings.”

20 Speech walk messages shall not contain any additional information, except they shall include designations such as “Street” or “Avenue” where this information is necessary to avoid ambiguity at a particular location. (Section 4E.11, P17 - 20)

Recent research evaluated localizability and detectability of speech messages, developed recommended message wording, and determined that response to speech messages was more accurate than responses to two different tones, when pushbuttons were on the same pole (see Appendix C).

How used by pedestrians who are blind or who have low vision

The audible WALK indication provides a clear cue to the beginning of the pedestrian phase. Pedestrians who are blind or who have low vision will evaluate traffic and the intersection, then listen for the WALK indication. After hearing the WALK indication, they typically check that traffic has stopped and no cars are turning across their path before beginning their crossing.

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Vibrotactile WALK indication

Description

The raised arrow on the APS pushbutton vibrates during the WALK interval.

Additional information

Vibrotactile information is useful when pedestrians can be aligned and prepared for crossing while still keeping a hand on the APS.

Those who are deaf or hard of hearing must also know where to find the device since the pushbutton locator tone is not helpful.

When to use

The vibrotactile indication of the WALK interval is needed at most locations and is required by the MUTCD . However, it is useful only when the device is located close to the crossing departure location.

It is important to note that the MUTCD requires audible information in addition to vibrotactile indications of the WALK. Without specific training on the device, blind pedestrians may not find or use the vibrotactile indication, particularly if it is not located on the actual pushbutton.

References

Figure 4-1. Pedestrian waiting to feel the vibrotactile WALK indication

Figure 4-1. Pedestrian waiting to feel the vibrotactile WALK indication

MUTCD standard states that: "Vibrotactile walk indications shall be provided by a tactile arrow on the pushbutton (see Section 4E.12) that vibrates during the walk interval. MUTCD 2009 Section 4E.11, P3)

How used by pedestrians who are blind or who have low vision

Pedestrians will stand beside the pushbutton with their hand on the arrow while waiting to cross. When the arrow begins vibrating, they will check for traffic and begin their crossing. The vibrotactile indication communicates to pedestrians who are deaf-blind that the WALK interval is in effect and may provide confirmation of the WALK interval to pedestrians who are blind at a particularly noisy intersection.

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