Bruce A. Gardner
October 22, 2002
To Whom It May Concern:
I am writing to express my concerns as a blind person over the draft guidelines
that the Access Board has issued mandating audible traffic signals at all
intersections with "walk/don't walk" signs and requiring detectable warnings to
be placed at every street crossing without exception. The current guidelines as
drafted will be extremely detrimental to the travel safety of blind people.
Despite the intention of the guidelines to make travel more safe for blind
people, mandating audible traffic signals will create an environment at each and
every intersection where as many as 8 or more separate tones will be going off.
This array of varying tones will not only create confusion at every intersection
and make it difficult to discern the tones, but will drown out the critical
traffic sounds that are necessary for blind people to utilize to determine when
it is safe to enter the roadway. The added noise will create an extremely
Any guidelines that are adopted should emphasize the following:
Audible Traffic Signals
* Most intersections do not require an ATS for the accessibility and safety of
* Only those intersections with complex geometry, complex signalization, or
varied signalization for each lane may be appropriate for an ATS.
* Vibrotactile indicators should be used in preference to audible signals in
order to minimize noise distractions and better promote safety.
* Locator tones should not be included in the final guidelines and may be
subject to further research.
* At most intersections, the built environment provides ample accessible cues to
determine the difference between the sidewalk and the street.
* A slope of less than 1:15 in crossing from the sidewalk to the street
(including medians and islands) may not be detectable and should be identified
with a detectable warning.
Bruce A. Gardner