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Rating Scales
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Prioritizing APS installations

Existing intersections
As discussed previously, this prioritization information is to be used in prioritizing existing intersections for retrofit with APS either in response to requests, or in updating an ADA transition plan.

Establishing priorities
Prioritization schemes should place only limited emphasis on factors related to frequency or likelihood of use by blind pedestrians. The information provided by APS may be necessary at any time, along any route, to residents, occasional travelers, and visitors. Intersections having high pedestrian volumes are likely to have pedestrians whose vision is sufficiently impaired that they have difficulty using conventional pedestrian signals.

Of greater importance are factors related to determining whether sufficient acoustic information exists - at all times - to permit safe crossing at a particular intersection.

Rating scales
Several rating scales have been developed, some of which have been utilized for over 20 years. These rating scales are used in different ways in different cities.
  • In some locations, they were developed as warranting schemes and APS were not installed unless the intersection met a required minimum number of points.
  • Other cities use rating scales only to aid in prioritization.
Generally, points are assigned to specific intersection features, as well as proximity to services for all pedestrians, such as transit, government offices, or shopping. San Diego, Los Angeles, Portland, Oregon, and Maryland Department of Transportation use point rating scales as part of their process. Their scales are included as examples and information about their process is discussed in this section.

After a request for an APS is made by an individual who is blind or by an organization representing or serving individuals who are blind or visually impaired, the intersection is evaluated using a rating scale.

Individual crossings

Systems developed most recently rate each crossing at an intersection rather than the whole intersection.
  • The developers of these schemes have recognized that certain crossings of an intersection may not be problematic, while other crossings of the same intersection may not have sufficient auditory information
  • This change reflects recent developments in types of APS available as well, which may allow installation on particular crosswalks of an intersection without providing confusing cues to individuals at other crosswalks.
Who evaluates?
Systems for determining the priority of APS installations usually involve participation of one or more representatives of three groups of experts: traffic engineers, orientation and mobility specialists, and pedestrians who are blind.

Different persons in different jurisdictions carry out the evaluation.
  • In San Diego, a traffic engineer and an orientation and mobility specialist rate separate aspects of the intersections.
  • In Los Angeles and Portland, the rating is conducted jointly by an orientation and mobility specialist and the traffic engineering department staff member.
  • In Maryland, the DOT engineer determines the rating.
Prioritizing based on ratings
In San Diego and Portland, the ratings are reviewed by an advisory committee of stakeholders, including blind citizens, that assists the traffic engineering department in prioritizing the installations.

Intersections with the highest number of points are generally considered highest priority, however, date of request, plans for other construction at the intersection in question, and other issues may affect priority of the installation.

Research on a rating scale
As part of NCHRP Project 3-62, a prioritization rating scale will be validated.

After completion of this project, the rating scale will be available for use by jurisdictions involved in prioritization decisions.

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