An engineering study of signalized intersections for each TxDOT district is needed to determine priority for providing APS at pedestrian signals. The Intersection Prioritization Tool should be completed by engineering staff. However, the study may include the input of an Orientation and Mobility Specialist. The Texas Workforce Commission, Vocational Rehabilitation Services, can be a good point of contact for consultants on orientation and mobility. TxDOT districts should develop a plan for upgrading pedestrian signals based on the priority established by the engineering study.

The TMUTCD provides the following information on the APS study:

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Guidance:

If a particular signalized location presents difficulties for pedestrians who have visual disabilities to cross the roadway, an engineering study should be conducted that considers the needs of pedestrians in general, as well as the information needs of pedestrians with visual disabilities. The engineering study should consider the following factors:

Research information indicates other considerations to study. According to the NCHRP publication

Accessible Pedestrian Signals - A Guide to Best Practices

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“Too little traffic is as great a problem to pedestrians who are blind, as is too much traffic. In the absence of APS, blind pedestrians must be able to hear a surge of traffic parallel to their direction of travel in order to know when the walk interval begins. Locations that may need APS include those with:

Where these conditions occur, it may be difficult for pedestrians who are visually impaired or blind to determine the onset of the walk interval by listening for the onset of parallel traffic, or to obtain usable orientation and directional information about the crossing from cues that are available.”

There are potential traffic conflicts associated with signalized pedestrian crossings to be aware of whether audible APS systems are installed or not. These include: vehicles still clearing the intersection when the audible signal comes on, vehicles that fail to stop for the red light, motorists who stop and make a right turn on red while watching to the left and failing to notice pedestrians on their right, and vehicles that may turn right or protected on the same phase as the pedestrian.

Adjustments to vehicular phases and allowable movements, including prohibiting right turn on red, may need to be incorporated into the overall intersection operation. It may even be questionable whether the audible signal interferes with the sight impaired traveler’s ability to listen for these possible conflicts. These potential conflicts require that due caution be used when crossing a street whether there is an audible signal or not. Speech messages should never indicate that it is safe to cross, but rather that a walk light is on.