U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
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The pedestrian facilities at intersections must be usable by pedestrians of all ages and capabilities. Intersections in particular must be designed to safely accommodate pedestrians of all ages and physical and mental abilities. Often, however, intersection designs fail to accommodate people with visual and mobility disabilities.
Figure 1: Intersections should accommodate all pedestrians
Intersection pedestrian features have traditionally been designed for people who are mentally and physically agile, with good stamina, vision, and hearing. However, according to the Census Bureau, approximately 15 percent of people age 5 or older have some disability.1 This represents more than 41 million individuals.
The Americans with Disabilities Act (ADA) provides minimum design standards that are to be applied to all public environments, including the public right-of-way. These standards, the Americans with Disabilities Act Accessibility Guidelines (ADAAG), are the foundation for designing all pedestrian environments. Additional, specific requirements for public rights-of-way are currently in draft form.
Pedestrian accessibility enhancements not only benefit people with disabilities; they benefit all pedestrians as well. Examples include curb ramp improvements that assist people pushing carts or strollers and placing the WALK push buttons in a place that is accessible and easily understandable for all intersection users.
Rather than a standard for dimensions, the ADAAG should be considered minimum criteria. Entities are encouraged to design and set codes beyond the minimum standards to facilitate access for a wider spectrum of people. If designers are faced with designing a facility not specifically addressed within the guidelines, they are still responsible for making the features/facility accessible. The nondiscrimination requirements for usability by people with disabilities in ADA are the overarching regulations that must be applied.2 It is critical for transportation providers to understand the details and principles for accessible design in order to apply good engineering judgment in difficult design situations. Pedestrian facilities with physical barriers, unusable sign and signal information, gaps in the system, and poorly designed features have critical safety implications for people with disabilities and may leave them stranded and unable to get to their destinations.
For pedestrians with disabilities, intersections can prove to be a challenge. Some of those challenges and design recommendations to better accommodate pedestrians with disabilities include the following:
Curb ramps are required at all crossings to provide access for pedestrians who use wheelchairs or who cannot step off a curb. Ideally, a separate curb ramp should be provided for each crosswalk (See Figure 3, which shows a curb ramp on only one side of the street). The ramp should have no more than 8.33% running slope and no more than 2% cross slope. A level landing/turning space is required at the top of a perpendicular ramp. Truncated dome detectable warnings are required at the transition to the street where there is no curb, to alert pedestrians who are blind to the edge of the street. Where possible, the curb ramp should be aligned with the direction of travel on the crosswalk so individuals with disabilities are properly aligned to cross and don't have to turn after entering the street. Design guidance for curb ramps in new construction and in alterations situations can be found in Designing Sidewalks and Trails for Access, Part 2, published by FHWA in 2001, and in Special Report: Accessible Public Rights-of-Way, Planning and Designing for Alterations, published in 2007 by the Institute of Transportation Engineers and the Access Board.
Figure 3: View of a new perpendicular ramp with returned curbs on one side of the street, but vertical curb prevents passage on opposite side of the street
Figure 4: Example of a too steep cross slope
Curb ramps at intersections need to be designed so that they do not create an inaccessible condition for the pedestrians using the sidewalk and not crossing the street. The primary problem encountered in maintaining an accessible route is ensuring a 3-foot wide path with a cross slope of 2% or less is provided through the intersection (Figure 4 shows a cross slope that is too steep. This makes it difficult for a wheelchair user to negotiate a pedestrian accessible route).
At intersections, turning vehicles and the speed at which they travel pose the greatest threat to pedestrians, and often the motorist's attention is focused on other motorists.
Skewed intersections can be especially problematic for pedestrians with mobility impairments. While the shortest crossing distance of a roadway occurs at aright angle, this is not usually the best approach for striping crosswalks at skewed intersections. Crosswalks at skewed intersections should be striped parallel to the adjacent roadway. The alternative, a crossing perpendicular to the roadway, places pedestrians out of the intersection area where motorists expect and are looking for conflicts. Accessible pedestrian signals (APS) should be used to provide positive guidance to pedestrians with vision impairments.
Right-turn-on-red, roundabouts and channelized right-turn lanes and other features designed to move traffic more quickly can be hazardous for people with visual disabilities. Pedestrians who are blind or who have low vision typically rely on the sounds of traffic stopping and starting as cues to signal phases, or to gaps in traffic as cues to cross at unsignalized locations.
In roundabouts and channelized turn lanes, sound created from constantly moving traffic from other lanes may mask the sound of a vehicle in the immediate lane being crossed. While a pedestrian who is sighted can cross in a gap just after a vehicle has crossed the crosswalk, a pedestrian who is blind may have to wait until the sound of that vehicle has faded before being able to tell if there is a gap in traffic.
At many intersections, pedestrian push buttons are located two per pole or are located such that the crossing they serve is unclear. Place pedestrian push buttons on the far side of the curb ramp (away from the parallel roadway) and perpendicular to the crossing.
The Manual on Uniform Traffic Control Devices (MUTCD) provides guidance and standards for accessible pedestrian signals in 4E.06 and 4E.09 (ref. 2003 MUTCD) and the MUTCD Notice of Proposed Amendment provides more specific criteria, based on new types of APS. New types of APS are integrated into the pedestrian push button and include speakers and vibrating surfaces incorporated in the pedestrian push button housing. These provide crossing indications to the waiting pedestrian at the departure curb rather than from overhead, as in older technology, and permit speaker volume to be set at a significantly lower and less obtrusive level. Tactile arrows and other features—push button locator tones, additional audible or Braille information, crosswalk maps, actuation indicators—enhance the effectiveness of these new devices.
Figures 5 and 6 show several of the push button-integrated APS devices available in the United States. All include a push button that is at least 2 inches in diameter, both audible and vibrotactile WALK indications, a push button locator tone, a tactile arrow and automatic volume adjustment. Configuration, functioning and adjustment methods vary somewhat by manufacturer.
Figure 5: APS example
Figure 6: Examples of APS
Most push button-integrated APS can provide additional features. These may include Braille labels for street names, actuation indicators (a light or beep), tactile crosswalk maps, and options activated by an extended button push: audible beaconing (useful for directional guidance at irregular or long crossings), extended pedestrian timing and recorded information of street names or additional information about the intersection.
For further information, see NCHRP Web-only Document 117A, Accessible Pedestrian Signals: A Guide to Best Practice.
APS should be considered when:
Designing for accessibility is largely a matter of common sense on the part of the designer or engineer, once there is awareness and understanding. It means understanding the capabilities of users (children, elderly, people with cognitive, visual, and mobility disabilities) and knowing how a facility should perform for all pedestrians.
Some questions to ask:
AASHTO Guide for the Planning, Design and Operations of Pedestrian Facilities, AASHTO, Washington, DC, 2004.
Barlow, Janet, Pat Cannon, Dan Dawson, et. al. Building a True Community: Final Report. Public Rights-of-Way Access Advisory Committee, for the U.S. Access Board, February 2001. http://www.access-board.gov
Bentzen, Billie Louise, Ph.D., Janet M. Barlow, COMS, and Lee S. Tabor. Detectable Warnings: Synthesis Of U.S. And International Practice. May 2000. http://www.access-board.gov/publications/DW%20Synthesis/report.htm.
FHWA. Designing Sidewalks and Trails for Access: Best Practices Guide Part II of II. https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/sidewalk2/.
FHWA. Manual on Uniform Traffic Control Devices provides the standards (and proposed standards) for traffic control devices and included information on Accessible Pedestrian Signals (APS), Chapter 4E and Temporary Traffic Control Elements, Chapter 6D. http://mutcd.fhwa.dot.gov.
FHWA, National Highway Institute. http://www.nhi.fhwa.dot.gov/Home.aspx.
ITE Special Report: Accessible Public Rights-of-Way, Planning and Design for Alteration. Public Rights-of-Way Advisory Committee. Washington, DC, 2007.
ITE. Traffic Control Device Handbook. Washington, DC. Pedestrians, Chapter 13, 2001.
Pedestrian Facilities Design, National Highway Institute Course 142045, FHWA, Washington, DC. http://www.nhi.fhwa.dot.gov/home.aspx.
Noyce, David A., Ph.D., P.E. and Janet M. Barlow, COMS. Interfacing Accessible Pedestrian Signals and Traffic Signal Controllers. April 2003. http://www.access-board.gov/research &training/APS/report.htm.
Transportation Research Board: NCHRP Web-Only Document 117A: Accessible Pedestrian Signals: A Guide to Best Practices, UNC-HSRC & Accessible Design for the Blind, June 2007. http://www.accessforblind.org/.
1 US Census Bureau, 2006 American Community Survey http://factfinder.census.gov/home/saff/main.html.
2 It is not the intent, however, that agencies be required to purchase right-of-way for the sole purpose of meeting ADA criteria. http://www.access-board.gov/prowac/draft.htm#ta.3 MUTCD 2008 NPA, Section 4E.10, FHWA, Washington, DC, 2008. 4 The ADA Draft Public ROW Accessibility Guidelines state, "Each crosswalk with pedestrian signal indication shall have an accessible pedestrian signal which includes audible and vibrotactile indications of the WALK interval." http://www.access-board.gov/prowac/. 5 Ibid.
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