Tactile walking surface indicators (TWSIs) are typically comprised of attention fields [truncated domes—referred to in the United States as detectable warning surfaces (DWS)] and guiding patterns of raised parallel bars. The truncated domes and guiding patterns are combined to define paths of travel in pedestrian areas, including public rights-of-way and multimodal transportation facilities. Many countries make extensive use of TWSIs and some have adopted standards requiring them to aid wayfinding for travelers who are visually impaired.
There is increasing recognition in the United States that tactile guiding patterns may be an effective solution to wayfinding problems for visually impaired travelers where there are insufficient cues in the built environment for effective wayfinding. Examples are rail and transit stations and hubs; intermodal terminals; plazas; irregular and confusing intersections such as roundabouts and channelized turn lanes; alternative intersections; shared streets; and parallel pedestrian/cycle paths at the same level.
A number of U.S. and Canadian jurisdictions and transit authorities have begun to explore or to install guiding patterns and truncated domes. These include Caltrans; Los Angeles METRO; BART, VTA, and Samtrans in the San Francisco Bay Area; New York DOT; DC DOT; Sound Transit (Seattle); Minneapolis/St. Paul Region; Cambridge, MA; TransLink (Vancouver, BC); and Alexandria, VA. While most of these guiding pattern installations are raised bar surfaces, there is great variation in the installation and materials, including the width and height (detectability) of the guiding pattern and where it is located. Participants in trials have found that some of the surfaces used at shared streets and shared pedestrian/cycle paths are not detectable or provide poor cues for wayfinding.
Consistency in cues for wayfinding is extremely important to travelers who are blind or visually impaired in order for them to understand the message of such cues and because they are unable to use many other cues available to travelers with unimpaired vision. TWSIs, including both attention patterns (DWS) and guidance patterns (raised bars) are loosely standardized on the basis of then-existing research and practice in ISO 23599 Assistive Products for Blind and Vision-Impaired Persons–Tactile Walking Surface Indicators (2012).The only systematic use of TWSIs in the United States is DWS, which is required at transit platform edges, curb ramps, and other locations where there is no distinction in level between pedestrian and vehicular ways. Standards ensuring consistency for the surface texture and some consistency in the installation of DWS in the United States are contained in the 2006 Standards for Transportation Facilities and the 2010 Americans with Disabilities Act Standards. Similar consistency is needed in the surface textures and installation of guiding patterns. Research-based guidelines for TWSIs in the United States are urgently needed to enable transportation infrastructure designers, owners, and operators to provide travelers who are blind or visually impaired reliable to ways to find their way in transportation settings including:
Rail and transit stations and hubs, and intermodal terminals, including approaches to the facilities, concourses, mezzanines, and boarding platforms
Fare machines, turnstiles, emergency and information telephones, and places of refuge
Intersections and changes in the direction of travel indicated by guidance surfaces in stations or in street crossings
Shared streets, plazas, parking facilities, and other open spaces
Sidewalk-level separated bike lanes without a continuous sidewalk buffer
Crossings that are hard to locate using non-visual cues, such as at mid-block crossings, roundabouts, and channelized turn lanes
Intersections where the curb ramps are not aligned with the crosswalks
Complex or alternative intersections
Cold/adverse weather climates, including areas with snow and ice
The objective of this research is to produce guidance for transportation planners, engineers, and orientation and mobility specialists that will provide for consistency in the design, installation, and usability of TWSIs in multimodal transportation in the United States. There will be two products: (1) A Guide to Tactile Wayfinding in Transportation Settings for Travelers Who Are Blind or Visually Impaired, and (2) a final report that includes a review of U.S. and international research and practice, as well as the methods and results of human factors research conducted under this project.
Guidance resulting from this research should be appropriate for private entities, as well as the following bulleted entities seeking to provide wayfinding cues to improve the accessibility of their transportation networks:
- State, local, tribal, and territorial agencies, including
- Rail, transit, and highway agencies
- Public works departments, ferries, and airports
- Parks and recreation departments
It may also form the basis for recommended practices for consideration by the American Public Transportation Association, Institute of Transportation Engineers, National Association of City Transportation Officials, American Association of State Highway and Transportation Officials, or others.
The proposed research is focused on determining optimal technical specifications for selection, usability, installation, and maintenance of TWSIs in multimodal environments. All tasks should be coordinated with ongoing related research. The following major tasks are envisioned:
Task 1. Comprehensive review of TWSI research, standards, and current practice in the United States and internationally. Identify research shortfalls and gaps. Develop a draft research roadmap to lay out which items are to be covered in the subject project and which might be carried out elsewhere or in parallel projects. Parallel projects might cover topics such as tactile maps and auditory cues. Coordinated research projects might cover topics such as sidewalk-level separated bike lanes without a continuous sidewalk buffer and directional surface indicators at intersections.
Task 2. Develop a detailed Phase II research plan to conduct human factors testing to determine the detectability, discriminability, and usability of TWSIs in a comprehensive approach that integrates the existing standards for DWS (for example, truncated domes), guiding patterns (for example, bar tiles), and perhaps novel surfaces for special purposes. Identify potential implications for other travelers, including people with reduced mobility (for example, walker and wheelchair users). Develop an appropriate data collection protocol that maximizes collection efficiency, while assuring that the results are statistically meaningful.
Task 3. Develop a detailed Phase III research plan and data collection schedule to conduct human factors field tests of TWSIs with demonstrated detectability and discriminability, to validate their usefulness in ecologically valid wayfinding tasks, and to refine guidance for installation and maintenance.
The Phase III research plan will consider geographical diversity of test locations and other characteristics. At a minimum, the work plan should include the geometrics and operational conditions under which each potential solution selected is expected to be appropriate, the number of field sites required for testing, a list of proposed sites, the research methodology, and the evaluation and analysis criteria. It is acceptable to identify multiple wayfinding solutions to be tested at a given location. Identify potential implications for other travelers, including people with reduced mobility (e.g., walker and wheelchair users). Develop an appropriate data collection protocol that maximizes data collection efficiency, while assuring that the results are statistically appropriate. If available, case studies may be included to extend the breadth of work described.
Task 4. Develop a detailed outline for A Guide to Tactile Wayfinding in Transportation Settings for Travelers Who Are Blind or Visually Impaired. See Task 12.
Task 5. Submit an interim report, within 6-9 months of contract initiation, to document the results of Tasks 1 through 4 for review by the TCRP. The contractor will be expected to meet with the TCRP approximately 1 month later. A PowerPoint presentation (in accessible format) provided at the interim meeting should be suitable, after revision, for use by panel members and others in describing the research and for posting on the project website. The research agency shall not proceed to Phase II without TCRP approval of the interim report and the updated work plan.
Task 6. Revise the interim report (following the panel meeting) in an accessible format suitable for publication on the TCRP website. See Special Note.
Task 7. Execute the Phase II research plan in accordance with the approved work plan.
Task 8. Analyze the new data gathered in Phase II and compare the results with existing data gathered in Phase I, with an emphasis on establishing guidance for wayfinding procurement, installation, and training.
Task 9. Execute the Phase III research plan, including the field tests, in accordance with the approved work plan. Conduct focus groups with participants at each field test site to refine the recommendations for selecting and presenting wayfinding information in similar sites.
Task 10. Analyze the results of human factors testing and focus groups performed in Phases I, II, and III. Develop guidance for treatment installation to establish wayfinding. Recommend treatments and/or changes that could potentially be incorporated into existing transportation procedures and practice documents such as those listed in Task 14.
Task 11. Develop cost estimates for the solutions that are proposed. The estimates should include initial installation costs in both new construction and retrofits, as well as operations and maintenance costs over the life-cycle of the solutions.
Task 12. Develop A Guide to Tactile Wayfinding in Transportation Settings for Travelers Who Are Blind or Visually Impaired. Include standard drawings and specific examples for typical and atypical installations. For inspiration, see NCHRP Project 3-62, "Guidelines for Accessible Pedestrian Signals;" NCHRP Report 674: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities; FHWA’s Accessible Shared Streets: Notable Practices and Considerations for Accommodating Pedestrians with Vision Disabilities; and ACRP Research Report 177: Enhancing Airport Wayfinding for Aging Travelers and Persons with Disabilities.
A Guide to Tactile Wayfinding in Transportation Settings for Travelers Who Are Blind or Visually Impaired should be written for transportation planners, engineers, and orientation and mobility specialists to provide for consistency in the design, installation, and usability of TWSIs in multimodal transportation in the United States. The guide should include pictures, graphics, charts, and any practical, user-friendly, and actionable steps that transportation practitioners can use to implement tactile improvements. The guide should include an executive summary, a brief recap of the underlying research, lessons learned, and sample justifications for funding to implement the recommended practices.
Task 13. Provide a stand-alone technical memorandum titled “Implementation of Research Findings and Products.”
Task 14. Submit a final report that documents the entire research project. At a minimum, the report should include a summary of all tasks completed, details of the work conducted to select the wayfinding solutions evaluated in Phase II and Phase III, complete documentation of the experiments performed, guidance proposed in Task 12, a summary of the cost information developed in Task 11, and any changes in recommended transportation engineering procedures or practices resulting from this research. Where appropriate, the report should include appendices with recommended language for potential inclusion in the AASHTO Policy on Geometric Design of Highways and Streets; the AASHTO Guide for the Planning, Design, and Operation of Pedestrian Facilities; the AASHTO Guide for the Development of Bicycle Facilities; the FHWA Manual on Uniform Traffic Control Devices; the ITE Traffic Control Devices Handbook; and other appropriate documents.
Note: Following receipt of the Task 14 preliminary draft final deliverables, the remaining 3 months shall be for TCRP review and comment and for research agency preparation of the revised final deliverables.
Note: It is anticipated a follow-on project will develop training and outreach materials, emphasizing safety.
Accessible formats: Reports must comply with Section 508 of the Rehabilitation Act (29 U.S.C. 794d), as amended by the Workforce Investment Act of 1998 (P.L. 105-220), August 7, 1998. Resources are available at http://www.section508.gov/.
The recommended work plan detailed in the interim report will be designed to obtain the data needed to balance the needs of various modes including both motorized and non-motorized facility users. Specifically, exploration of the proper balance among the needs of passenger cars, trucks, pedestrians (including pedestrians with vision disabilities and reduced mobility), and bicycles is central to achieving the objectives of the research. The work plan will show the specific research needed to address the needs of these various users. The work plan will also detail the criteria for evaluating the effectiveness of the potential solutions studied in Phase II and Phase III.
Useful resources for this project include:
- ISO Standard 23599, Assistive Products for Blind and Vision-Impaired Persons -- Tactile Walking Surface Indicators https://ec.europa.eu/eip/ageing/standards/healthcare/personal-autonomy/iso-235992012_en
- Metro (the Los Angeles County Metropolitan Transportation Authority) Systemwide Station Design Program https://www.metro.net/projects/systemwidedesign/
- FHWA’s Accessible Shared Streets: Notable Practices and Considerations for Accommodating Pedestrians with Vision Disabilities https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/accessible_shared_streets/index.cfm
- Research on Utilization of Tactile Tiles and Behavior of Visually Impaired Persons on Railway Platforms https://www.jstage.jst.go.jp/article/rtriqr/43/2/43_2_58/_pdf
- Guidebook for the Proper Installation of Tactile Ground Surface Indicators (Braille Blocks): Common Installation Errors http://www.iatss.or.jp/common/pdf/research/h966_e.pdf
- NCHRP Web-Only Document 150: Accessible Pedestrian Signals: A Guide to Best Practices (Workshop Edition 2010) http://www.trb.org/Publications/Blurbs/164696.aspx
- NCHRP Report 674: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities http://www.trb.org/Publications/Blurbs/164715.aspx
STATUS: Research in progress. An interim meeting of the panel with the research team was held in November 2019. Laboratory and field tests are anticipated in 2021.