Section 4: Accessible Pedestrian Signals GuidelinesAnchor: #i1009717
The purpose of this section is to provide guidelines for the installation of Accessible Pedestrian Signals (APS).Anchor: #i1009738
An APS is a device that communicates information about pedestrian signal timing in non-visual format such as audible tones, verbal messages, and/or vibrating surfaces - Texas Manual on Uniform Traffic Control Devices (TMUTCD).Anchor: #i1009771
In June of 2002, the U.S. Access Board released a draft document entitled Draft Guidelines for Public Rights-Of-Way. These draft guidelines required APS systems at all new signalized intersections where pedestrian signals are installed. In November 2005, new draft guidelines were issued. The November 2005 draft guidelines also include requirements for APS to be installed on new construction where pedestrian signals are installed. The 2005 draft guidelines state:
“The Board’s aim is to ensure that access for persons with disabilities is provided wherever a pedestrian way is newly built or altered, and that the same degree of convenience, connection, and safety afforded the public generally is available to pedestrians with disabilities. The guidelines would not require alterations to existing public rights-of-way, but would apply where a pedestrian route or facility is altered as part of a planned project to improve existing public rights-of-way.”
The Americans with Disabilities Act (ADA) requires that when pedestrian facilities are provided, they must be usable by all pedestrians. The Federal Highway Administration (FHWA) stresses that the draft guidelines should be considered as best practices and the state of practice and should be followed regarding issues not covered by the existing ADA guidelines.
The following recommended practice is based on the above mentioned draft guidelines that were developed through the FHWA.Anchor: #i1009850
Until such time that further rules or regulations are provided by the U.S. Department of Transportation (USDOT), FHWA, U.S. Department of Justice (USDOJ), the U.S. Access Board, the Texas Department of Licensing and Regulation (TDLR), the American Association of State Highway Transportation Officials (AASHTO), or others, the installation of APS will be in accordance with the guidance that follows. This recommended practice is subject to change and will be updated as needed. Additionally, an Intersection Prioritization Tool based on National Cooperative Highway Research Program (NCHRP) Project 3-62 should be utilized to evaluate signalized intersections for the need of APS based on comparative need. Priority to install APS systems will also depend on whether the signalized intersection is considered to be part of new construction, part of a modification project, or an existing installation as defined below.
- New Construction - New construction of traffic signals is considered either the installation of a new traffic signal at a previously non-signalized intersection or substantial replacement of a traffic signal. If pedestrian signals are installed, the traffic signal shall be designed and equipped with APS for all crosswalks that are to be equipped with pedestrian signals. Installation of APS will not be considered at intersection approaches where an engineering study has determined that pedestrian signals are to be prohibited. However, the designer should take into consideration that a non-visual format to prohibit pedestrian crossing (some sort of physical means of prohibiting the crossing such as railing, heavy vegetation, etc.) be provided in addition to crossing prohibition signs.
- Traffic Signal Modifications - Traffic Signal Modifications are considered to be the modification of an existing traffic signal at an intersection. If there are existing pedestrian signals, or pedestrian signals are being added as part of the installation, the design should include the installation of APS. Installation of APS will not be considered where pedestrian crossings are physically prohibited. Minor signal modifications such as installation of left-turn signal heads, modification of existing signal phasing, or installation of vehicle detection systems that do not require substantial reworking of the intersection signal poles or wiring would not require a redesign of the intersection as mentioned above.
- Existing Traffic Signals - TxDOT districts will schedule an evaluation of all existing signalized crosswalks at signalized intersections under their jurisdiction. Evaluations will include completion of the Intersection Prioritization Tool worksheet. Crosswalks should be evaluated to determine a priority for the installation of APS. The scores should be arranged in order from the highest to the lowest. Crosswalks with scores in the top 50 percent and associated with a specific request should be considered high priority. Districts shall develop a plan for installation of APS at all intersections with existing pedestrian signals based on the order established by the determined priority. Additionally, evaluations will be made when there is a written request for a specific intersection(s). Evaluations that result in a high priority or are associated with a specific request should be scheduled to have APS installed. At the completion of the high priority or specific request projects, the district should review the plan and move toward completing all APS installation.
- Engineering Judgement - Based on the engineer’s judgement, a higher priority may be given to the installation of APS at a crosswalk than an initial evaluation of the crosswalk would indicate.
Engineering Study for APS
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 Department of Assistive and Rehabilitative Services (DARS), Division for Blind 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:
“Guidance: The installation of accessible pedestrian signals at signalized locations should be based on an engineering study, which 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; and
- E. The complexity of intersection geometry.”
Research information indicates other considerations to study:
“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:
- intersections with vehicular and/or pedestrian actuation
- very wide crossings
- major streets at intersections with minor streets having very little traffic
- t-shaped intersections
- non-rectangular or skewed crossings
- high volumes of turning vehicles
- split phase signal timing
- exclusive pedestrian phasing, especially where right-turn-on-red is permitted
- a leading pedestrian interval.
Where these conditions occur, it may be difficult for pedestrians who are visually inpaired 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.”1
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 left 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 interfears 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.Anchor: #i1009921
The draft Americans with Disabilities Act Revised Draft Guidelines for Accessible Public Rights-of-way ( http://www.access-board.gov/prowac/draft.htm) include specific requirements for pedestrian signals and a comprehensive list that the designer should review.
The TMUTCD, Section 4E. “Pedestrian Control Features” also covers many of the design requirements of APS systems. As with any traffic control device, the TMUTCD should be reviewed when designing accessible pedestrian signals. For example, the TMUTCD indicates that the push buttons should be separated by 10 feet and located near the curb ramp they serve, preferably at the landing for the curb ramp.
To comply with the Texas Accessibility Standards (TAS), the push button must be centered on a clear ground space. If the curb ramp landing is not utilized, an additional level area landing at the push button may be required. The APS units require mounting with proper orientation to direct pedestrians across the street.
The Accessible Pedestrian Signals: Synthesis and Guide to Best Practice, which was developed by the NCHRP, is very comprehensive in regard to all aspects of APS. It goes into extensive detail regarding all aspects of APS and is recommended as a reference for APS design considerations.
APS have undergone several advancements throughout the years. The most current devices are the push button integrated systems. With these systems, the speaker, push button, and vibro-tactile arrow are all contained in the push button housing. Placement of the push button/APS is critical to the proper operation of the system. The pedestrian uses the arrow on the APS for orientation in crossing the street. The button stations serving adjacent crosswalks at the same corner require separation so that the user can tell which crossing is being served with a walk indication. The APS provides a locator tone and “walk” tone; the cuckoo and chirp tones are no longer considered effective. These systems have the capability to adjust to ambient noise levels and can be configured so that they are only discernable from a specific distance from the intersection, posing less of a noise issue for the surrounding environment. In consideration of the above, it is critical in design to locate the pushbuttons and crosswalks such that the installation of APS will be effective.Anchor: #i1012413
When specifying an APS, it is necessary to know what will be needed at the crossing. It is recommended that a push button integrated APS system be specified. These systems have all the TMUTCD required features such as locater tones, volume control, vibro-tactile arrows, etc. Contact TRF for assistance with specifications.Anchor: #i1012807
2006 Texas Manual on Uniform Traffic Control Devices (TMUTCD)
November 23, 2005 Revised Draft Guidelines for Accessible Public Rights-of-Way (U.S. Access Board)
NCHRP 3-62 Accessible Pedestrian Signals: Synthesis and Guide to Best Practice
Texas Accessibility Standards
Transportation Research Record, Journal of the Transportation Research Board, No. 1982, pp. 13-20, titled, “Development of Intersection Prioritization Tool for Accessible Pedestrian Signal Installation”
1 Accessible Pedestrian Signals - A Guide to Best Practices, Developed under the sponsorship of the National Cooperative Highway Research Program ( http://www.apsguide.org/index.cfm).Anchor: #i1013307
Intersection Prioritization Tool Worksheet
The Intersection Prioritization Tool provided through the link and available from the Traffic Operations Division was recreated from National Cooperative Highway Research Program (NCHRP) 3-62 research. The worksheets are a product of NCHRP 3-62 and are published in the Transportation Research Record, Journal of the Transportation Research Board, No. 1982, pp. 13-20, entitled “Development of an Intersection Prioritization Tool for Accessible Pedestrian Signal Installation”. The Intersection Prioritization Tool consists of two worksheets.
- The Intersection Worksheet accounts for intersection characteristics and layout, signalization type, and location related to transit facilities, facilities for the visually impaired, and major pedestrian attactions.
- The Crossing Worksheet accounts for the individual crossing characteristics. Each crossing at the intersection is rated based on several factors including:.
- crossing width
- speed limit
- pedestrian signal control
- vehicle signal control
- off-peak traffic presence
- availability of alternative APS
- requests for APS installation.
The Intersection Prioritization Tool provides a method of scoring individual crossings for relative crossing difficulty to visually impaired individuals. This provides a method to compare crossings for priority for installation of APS systems. In general, if one crossing generates a high priority, it would be desirable to provide APS for all crossings at the intersection.
The detailed instructions on the correct method for filling out and completing the worksheets are available on the internet at http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w117a_appendix-d.pdf).