CHAPTER 1
Background
Wayfinding is possibly the greatest challenge in the urban environment for travelers who are blind or visually impaired. For these travelers, wayfinding requires knowing where you are, knowing how to get to a desired destination, and remaining on the route. This is particularly challenging in complex environments in which:
- many streets cross at odd angles
- street crossings are not necessarily at corners
- curb ramps do not necessarily slope in the direction of travel on associated crosswalks
- there are not always good vehicular cues to aid in establishing a heading for street crossing or maintaining a correct heading while crossing
- there are large open spaces that must be traversed
- there is often limited accessible wayfinding information
One of the first attempts to provide accessible wayfinding information for travelers who are blind or visually impaired was the installation of a system of tactile walking surface indicators (TWSIs) in Japan in the 1960s. Subsequently, there has been some research to standardize TWSI geometry, and various TWSIs have been installed, usually comprising raised truncated domes and raised bars. However, the research is not comprehensive, and not all is applicable to the United States.
In recent decades, numerous wayfinding technologies have been developed to overcome travel challenges in the built environment; however, not all travelers who are blind or visually impaired have access to these technologies or are able to use them. Accordingly, TWSIs remain an important way to provide wayfinding information.
Consistency in wayfinding cues is essential to their effective use. There is a U.S. standard for TWSIs to warn of vehicular danger through truncated dome detectable warning surfaces (DWSs), which was based on research on detectability. However, there is no standard for guiding surfaces (tactile directional indicators, TDIs). Additionally, there has been no U.S. research to base standards on for combined DWSs and TDIs that function effectively together as a TWSI system. These surfaces must be not only detectable but discriminable from one another. The need for consistency in TWSIs and guidelines for their use in multimodal environments is the rationale for the work of this project.
Study Objectives and Scope
There are three major objectives to this project:
- Determine through empirical research the detectability, discriminability, and usability of TWSIs used together in a guide system.
- Validate the usability of TWSIs with demonstrated detectability and discriminability under a variety of geometric and operational conditions and across a range of diverse transportation settings.
- Produce a guide that speaks to a broad audience based on those empirical results that provides consistency in design, installation, and usability of TWSIs in multimodal environments.
Organization of Report
Chapter 2 gives an overview of what is known about TWSIs, what standards exist, and what the state of the practice is relative to their use primarily in the United States. Supplemental details from a comprehensive literature review and assessment of the state of the practice is provided in Appendices A and B. Chapter 3 discusses the three experiments conducted to complete the research approach and explains the eligibility criteria, recruitment process, and session plans for study participants. Chapters 4, 5, and 6 provide detailed accounts of the three experiments completed—their settings, what was tested and the procedures used, how the data was analyzed, and their findings and conclusions. The data collection sheets used for each experiment are in Appendix C. Chapter 4 focuses on detection and identification trials conducted in a controlled environment (experiment 1). Chapter 5 relays experiment 2, which investigated how participants navigated TWSIs in a controlled environment. The third experiment, using and navigating TWSIs in a natural environment, is laid out in Chapter 6. Finally, Chapter 7 presents conclusions from the project and posits suggestions for further research needed based on gaps identified through a review of the literature, lingering questions not addressed through this project, and questions that emerged from the results of the experiments conducted for this project.
