Prioritizing APS Installations
The information regarding prioritizing intersections for installation of APS is not intended for application to new or reconstructed intersections. In new construction or reconstruction projects, it is appropriate to consider the Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way (proposed PROWAG) or Draft PROWAG as the best guidance available at this time (Isler memo, 2006). In new construction, APS should be installed wherever pedestrian signals are installed.
Where are APS needed?
When considering and prioritizing crossings and intersections for retrofit with APS, consideration needs to be given to the information available to pedestrians who are blind and which crossings are in greater need of the APS. A number of factors enter into that decision.
The MUTCD Section 4E.0 9 recommends: " 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:
The installation of accessible pedestrian signals at signalized locations should be based on an engineering study, which should consider the following factors:
- Potential demand for accessible pedestrian signals;
- A request for accessible pedestrian signals;
- Traffic volumes during times when pedestrians might be present; including periods of low traffic volumes or high turn-on-red volumes;
- The complexity of traffic signal phasing (such as split phases, protected turn phases, leading pedestrian intervals, and exclusive pedestrian phases); and
- The complexity of intersection geometry."
Locations that may need APS include those with:
- Vehicular and/or pedestrian actuation
- Very wide crossings
- Crossings of major streets where minor streets have minimal or intermittent traffic (APS may be needed for crossing the major street)
- T-shaped intersections
- Non-perpendicular or skewed pedestrian crossings
- Low volumes of through vehicles
- High volumes of turning vehicles
- Split phase signal timing
- Exclusive pedestrian phasing, especially where right-turn-on-red is permitted
- Leading pedestrian intervals
Where these conditions occur, it may be impossible for pedestrians who are visually impaired or blind to determine the onset of the WALK interval by listening for the onset of parallel traffic. It would also be difficult to obtain usable orientation and directional information about the crossing from the cues that are available. Too little traffic is as great a problem for pedestrians who are blind as 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.
Advisory committee involvement
Some jurisdictions may wish to set up a process where ratings are reviewed by an advisory committee of stakeholders, including blind citizens, O&M Specialists and transportation professionals, that assists the traffic engineering department in the process.
In many of the current systems used, crossings with the highest number of points are generally considered highest priority. However, date of request, plans for other construction at the intersection, and other local issues may affect priority of installations.
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