Review of Design Guidance
Current Guidance
The MUTCD Section 4E.09 recommends: Â 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:
- A. Potential demand for accessible pedestrian signals;
- B. A request for accessible pedestrian signals;
- C. Traffic volumes during times when pedestrians might be present, including periods of low traffic volumes or high turn-on-red volumes;
- D. The complexity of traffic signal phasing (such as split phases, protected turn phases, leading pedestrian intervals, and exclusive pedestrian phases); and
- E. The complexity of intersection geometry.
Proposed and Draft PROWAG requires audible and vibrotactile indications of the WALK interval when new pedestrian signals are installed (see Chapter 5).
Principles
The following guiding principles should be kept in mind when installing APS. The APS installation should:
- Provide pedestrian signal information to those who cannot see the pedestrian signal head across the street
- Provide information to pedestrians about the presence and location of pushbuttons, if pressing a button is required to actuate pedestrian timing
- Provide unambiguous information about the WALK indication as well as which crossing is being signaled
- Use audible beaconing only where necessary
- Put as little additional sound in the environment as possible to avoid disturbance of neighbors and allow pedestrians who are blind or visually impaired to hear the traffic sounds, as well as the APS
New Construction — Ideal Installation
Figure 7-1. Ideal placement for pushbutton-integrated APS in the top corner of the flare of the curb ramp, next to the level landing
Providing audible and vibrotactile indications of the WALK interval, as specified in the MUTCD and Proposed PROWAG, means that devices should be integrated into a pushbutton unit, in order to provide vibrotactile WALK indications. The vibrotactile feature is a tactile arrow incorporated into the pushbutton device.
The ideal location for pushbutton-integrated APS is between the edge of the crosswalk line (extended onto the sidewalk) farthest from the center of the intersection and the side of the curb ramp. If at all possible, APS should be between 1.5 feet and 6 feet from the edge of the curb, shoulder, or pavement. However, in order to provide wheelchair access to the pushbutton, the pushbuttons must be located adjacent to a level all-weather surface. The control face and tactile arrow should be carefully aligned with the direction of travel on the associated crosswalk.
At corners of signalized locations where two pedestrian pushbuttons are provided, the pushbuttons should be separated by a distance of at least 10 feet (see Figure 7-1). A rapid tick WALK indication is required for installations following these guidelines about location.
Retrofit Installation — Constraints and Acceptable Solutions
Many APS installations will be a retrofit situation where they are being installed at an existing signalized intersection that is not being completely reconstructed. There will likely be infrastructure constraints that will make an ideal installation difficult.
Poles not located at ideal positions
If there are no poles at the recommended locations, options that should be considered, in order of decreasing desirability and from the standpoint of ambiguity, include:
- Repositioning of the pedestrian signals and poles, or the addition of stub pole(s) and associated conduit and wiring
- Two APS on a single pole with speech messages for the WALK indication, and additional features required with speech messages
- Use of pedhead-mounted speakers, possibly with mast arms or another provision in order to locate the WALK indication speakers as near to the associated crosswalk as possible (does not meet MUTCD requirement for vibrotactile indication of the WALK)
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