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Safety Toolbox: Engineering

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Accessible pedestrian signals

Accessible pedestrian signals (ASPs) supplement pedestrian signal indications with audible and/or vibrotactile information. These treatments include directly audible or transmitted tones, speech messages, Talking Signs, and vibrating surfaces.  They are intended make real-time pedestrian signal information accessible to pedestrians who are hearing or visual-impaired. Many different technologies exist. Newer signal types have a quiet, slowly repeating locator tone that indicates to approaching pedestrians that they must push a button to get a WALK signal and indicates the location of the push button. Directly audible or transmitted speech messages can identify the location of the intersection and the specific crosswalk controlled by that push button. A vibrating arrow at the push button can also be used to supplement the audible signals.
objective To accommodate the crossing needs of visually impaired pedestrians at signalized intersections.
applications For use at intersections with considerable traffic volumes and conflicts. There are three kinds of intersections at which Davis, California has considered using bicycle signals and which have subsequently become standard in California: at tee intersections with major bicycle movement along the top of the tee, at the confluence of an off-street bike path with an intersection, and where separated bike paths run parallel to arterial streets.
target population Disabled Pedestrians, All Pedestrians
crash type Pedestrian R/W Violation-Intersection, Pedestrian Violation-Intersection, Traffic Signals and Signs
  • The redundant auditory information results in getting all pedestrians to leave the curb faster, thereby speeding both pedestrian and vehicular flow.
  • Most accessible signal products in the USA are responsive to ambient sound, so they are not intrusive in neighborhoods.
  • Older types of audible pedestrian signals do not respond to ambient sound and are often either too loud or too quiet.
  • The directional guidance afforded by older type signals is poor, and they do not indicate to users whether they need to push a button.
  • May give ambiguous or incorrect information.
pointers Audible signals must be designed with careful attention to the surrounding land uses.  They provide helpful information that may speed pedestrian flow, especially at locations with high numbers of visually impaired pedestrians.
cost Low; approximately $400 to $600 per signal indication.
responsibility Public Works Department
further reading

Access Board, 2001. Building a true community: Final report, Public Rights-of-Way Access Advisory Committee, Washington, D.C. U.S. Architectural and Transportation Barriers Compliance Board. 

Americans with Disability Act Accessibility Guidelines for the Public Rights-of-Way (draft June 17, 2002) Washington, DC: U.S. Architectural and Transportation Barriers Compliance Board. 

Americans with Disabilities Act accessibility guidelines (July 26, 1991). Washington, DC: U.S. Architectural and Transportation Barriers Compliance Board. 36 CFR Part 1191 

Bentzen, B.L. (1997). Environmental accessibility. In B. Blasch, W. Weiner, & R. Welsh (Eds.). Foundations of Orientation and Mobility. 2nd ed. New York: American Foundation for the Blind. 317-356. 

Bentzen, B.L. & Tabor, L. (1998). Accessible Pedestrian Signals. Washington, DC, US Access Board. 

Barlow, J.M., Franck, L., Bentzen, B.L. and Sauerburger, D. (2001). Pedestrian clearance intervals at modern intersections: Implications for the safety of pedestrians who are visually impaired. Journal of Visual Impairment and Blindness. 95, 663-667. 

Bentzen, B.L., Barlow, J.M. and Franck, L. (2000). Addressing barriers to blind pedestrians at signalized intersections. ITE Journal. 70-9, 32-35. 

Bentzen, B.L., Barlow, J.M., and GubbÈ, D. (2000). Locator tones for pedestrian signals. Transportation Research Record. 1705, pp. 40-42. 

Bentzen, B.L., Crandall, W.F., and Myers, L. (1999) Wayfinding system for transportation services: Remote infrared audible signage for transit stations, surface transit, and intersections. Transportation Research Record 1671, pp. 19-26. 

Brabyn, J.A., Haegerstrˆm-Portnoy, G, Schneck, M.E. & Lott, L.A. (2000). Visual impairments in elderly people under everyday viewing conditions. Journal of visual impairment and blindness. 94: 741-755. 

Carroll, J. & Bentzen, B.L. (1999). American Council of the Blind survey of intersection accessibility. The Braille Forum 38, 11-15. 

Crandall, W.; Bentzen, B.L. & Myers, L. (1998) Remote Signage development to address current and emerging access problems for blind individuals. Part I. Smith-Kettlewell research on the use of Talking SignsÆ at light controlled street crossings. Report to National Institute on Disability and Rehabilitation Research. 

Crandall, W., Bentzen, B.L., Myers, L., and Brabyn, J. (2001) New orientation and accessibility option for persons with visual impairment: transportation applications for remote infrared audible signage. Clinical and Experimental Optometry. 84, 

Gallagher, B., Montes de Oca, P. Guidelines for Assessing the Need for Adaptive Devices for Visually Impaired Pedestrians at Signalized Intersections. (1998) Journal of Visual Impairment and Blindness, 92, 633-646. 

Hall, G., Rabelle, A. & Zabihaylo, C. (1994). Audible traffic signals: A new definition. Montreal: Montreal Association for the Blind. 

Hulscher, F. (1976). Traffic signal facilities for blind pedestrians. Australian Road Research Board Proceedings 8, 13-26. 

Murakami, T., Ishikawa, M., Ohkura, M., Sawai, H., Takato, J. and Tauchi, M. (1998). Identification of difficulties of the independent blind travelers to cross intersection with/without audible traffic signals. Proceedings: The 9th International Mobility Conference, Atlanta, GA. 

Oliver, M.B., Feagan, J.C., and Ardeliani, S.A. (1990) Audible Pedestrian Signals - Current Practices and Future Needs. ITE Journal 60(6) 35-38. 

San Diego Association of Governments. Evaluation of audible pedestrian traffic signals. San Diego Association of Governments, 1988. 

Szeto, A.Y.J. and Valerio, N.C., "Characteristics and Usage of Audible Pedestrian Traffic Signals," Proc. 5th Ann. Conf. Technology and Persons with Disabilities, March 1990, pp. 665-682. 

Szeto, A.Y.J., Valerio, N. and Novak, R., "Audible Pedestrian Traffic Signals: Prevalence and Impact," Journal of Rehabilitation R & D, 28(2):57-64, 1991. 

Szeto, A.Y.J., Valerio, N. and Novak, R., "Audible Pedestrian Traffic Signals: Analysis of Sounds Emitted," Journal of Rehabilitation R & D, 28(2):65-70, 1991. 

Szeto, A.Y.J., Valerio, N. and Novak, R., "Audible Pedestrian Traffic Signals: Detectability," Journal of Rehabilitation R & D, 28(2):71-78, 1991. 

Uslan, M.M., Peck, A.F. and Waddell, W. (1985). Audible traffic signals: How useful are they? ITE Journal, pp. 37-43. 

Van Houten, R., Malenfant, J., Van Houten, J. & Retting, R. (1997). Using auditory pedestrian signals to reduce pedestrian and vehicle conflicts. Transportation Research Record No. 1578. Washington, DC: National Academy Press. 

Wiener, W. R., Lawson, G., Naghshineh, K., Brown, J., Bischoff, A., & Toth, A. (1997). The use of traffic sounds to make street crossings by persons who are visually impaired. Journal of Visual Impairment & Blindness, 91, 435-445. 

Noyce, D., Barlow, J. (2003).  Interfacing Accessible Pedestrian Signals (APS) with Traffic Signal Control Equipment. University of Wisconsin at Madison and University of Massachusetts at Amherst.

examples City of Oakland, Public Works Agency
related tools Automated Pedestrian Detection, Educational Signs for Pedestrian Signal Indications, Pedestrian Signals, Countdown Signals, Scanning Eyes, Mid-block Signalized Crossings, Pedestrian Push Button Treatments

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