Tones or audible messages during clearance interval
A tone or other message sounds during the pedestrian clearance interval, at a different rate, tone, or with a different speech message, than the WALK indication or pushbutton locator tone. This can include audible pedestrian countdowns.
APS typically revert to the pushbutton locator tone during the flashing and steady DONT WALK interval. That is not considered to be a clearance interval indication/tone.
Clearance interval information is sometimes provided by APS in Japan and in some parts of Canada.
- In Japan, a variety of alternatives are available including a European emergency vehicle "ba-boo" sound, and various melodies.
- In Canada, it may be provided by a tone that repeats at a faster rate than the WALK signal. For example, if the WALK signal is a "cuckoo" at 1 time per second, during the clearance interval the "cuckoo" is sounded 2 times per second.
- Lets pedestrians who are visually impaired who have begun to cross the street know that the clearance interval prevails.
- The clearance interval sound might be mistaken for the WALK signal by someone who approaches during the clearance interval, leading them to begin crossing during the flashing DONT WALK.
- Pedestrians who are blind generally want to be able to hear traffic while crossing the street. The clearance tone or audible message could distract them from hearing traffic or mask the sound of traffic. The continuous nature of a speech countdown has more potential for masking other sounds than the shorter duration of the pushbutton locator tone.
- Additional cognitive processing may be required to interpret a verbal clearance interval message, such as an audible countdown.
- For a blind person, knowing the remaining length of the flashing DONT WALK signal is not useful since they don't have information about the remaining distance to the destination curb.
MUTCD addresses this in Paragraph 25 of Section 4E.11, stating: Following the audible walk indication, accessible pedestrian signals shall revert to the pushbutton locator tone (see Section 4E.12) during the pedestrian change interval.”
How used by pedestrians who are blind or who have low vision
This feature is not currently used in the US and is not recommended due to the potential confusion of the WALK interval with the clearance interval.
As noted in the disadvantages listed above, pedestrian countdown information is unlikely to provide any advantage to the individual who is blind or visually impaired.
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