QUESTION: Where an accessible route crosses a vehicular way, and
detectable warnings are required, do the detectable warning areas need
to be at the boundaries only, or along the entire pedestrian path across
the vehicular way?
DETERMINATION: Pursuant to the OSSC Section 1220.127.116.11, detectable
warnings required where an accessible route crosses a vehicular way, shall
be placed at the boundaries of the vehicular ways, not along the entire
pedestrian path across the vehicular way.
ANALYSIS: Detectable warnings shall consist of an approved texture,
and be 36" wide at the beginning and end of the accessible pedestrian
walkway adjacent to the vehicular way, even when the walkway continues
across the vehicular way. The OSSC Figure 42 in Chapter 11 does not show
this example as it only depicts the detectable warning area for a walkway
adjoining a vehicular way, not crossing it. However, the previous requirements
in the Americans with Disabilities Act Accessibility Guidelines (ADAAG),
(prior to the suspension of the federal detectable warnings texture requirement),
only required the boundary of the walkways at the entrance to and exit
of vehicular way to have detectable warnings.
Detectable warnings at transit platforms, curb ramps, vehicular areas
and reflecting pools were identified by ADAAG as being an aid for persons
with severe sight impairment to safely cross through these areas. In April
1994, the Access Board suspended the requirements for detectable warnings
at curb ramps, vehicular areas and reflecting pools so that further review
of the detectable warning textures at these areas can be further researched.
In Oregon, the OSSC did not remove the requirement for detectable warnings
in these areas, because the texture requirements are not limited to specific
A severely sight impaired person can use detectable warnings as a means
to attract their eyes downward and see the markings for the pedestrian
walkway and cross the vehicular area safely.
The maximum effect of detectable warnings is achieved when:
- The warning texture is unique so that it would not be confused with
other commonly-encountered surfaces in the environment;
- The warning location is adjoined or abutted to a hazard, or is where
it can signal an impending change in a walkway; and
- The warning extends in length beyond the average stride to allow
a pedestrian to sense it physically, understand its meaning and react
before the hazard or change is encountered.
ADAAG scoping requirements for detectable warnings and the technical
specifications for the type of texture or other means of identification
were developed to alert pedestrians of an imminent hazard and were not
intended for use as wayfinding devices.