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State of Oregon
Building Codes Division Staff 
Technical Advisory

The following advice applies to current code and conditions described in the question. Applications for similar situations may have different determinations.
PROGRAM: Structural Program
SUBJECT: Detectable Warnings at Vehicular Areas
SOURCE: 1996 Oregon Structural Specialty Code (OSSC)
REFERENCE: Section 1103.2.3.2
DATE OF ISSUE: February 26, 1997 
PREPARED BY: C. Darin Wilson, P.E., Code Specialist, (503) 373-1354

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 1103.2.3.2, 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 types.

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.