CHAPTER 3

Research Approach

Introduction

People who are blind must be able to accomplish three distinct tasks for any given TWSI to be useful alone and as part of a system: (1) detect the TWSI, (2) identify which type it is, and (3) understand what information it conveys based on its identity and the context. The research team devised and implemented three experiments to investigate how TWSIs could be used to aid people who are blind with these tasks.

• Experiment 1: The first study focused on detecting and identifying TWSIs. Two different geometries each of DWS and TDI were tested in a controlled environment to determine how detectable and identifiable they were overall, and to determine if any surfaces were more detectable and/or identifiable than any others. The height of the raised elements was the same, so the test focused on how differences in the gap spacing and top width dimensions may impact these measures. Not all the geometries of DWS currently allowed in the 2010 ADA standards have been verified as detectable through research, and there are concerns that those with narrower gap spacing may not be identifiable underfoot as a DWS and may therefore be more difficult to discriminate from TDIs. Chapter 4 summarizes experiment 1.
• Experiment 2: Results from experiment 1 informed the specific DWS and TDI used in experiment 2 to test how TWSIs may work as a simple system for following guide paths and identifying and correctly responding to turns, choice points, and endpoints in a controlled setting. A major question in experiment 2 was whether people with vision disabilities would have greater success following routes that included path intersections if an indicator were provided at those choice points (i.e., locations where paths intersect). Given the very limited previous research on discriminability between DWSs and TDIs when used together, this experiment also further explored discriminability. Details on experiment 2 are in Chapter 5.
• Experiment 3: Results from the previous two controlled-setting experiments, combined with findings identified in the literature review, informed the study design for this experiment, which sought to validate those findings by testing different TWSIs used together as a wayfinding system across different transportation settings in a real-world environment. This experiment deployed DWSs, TDIs, and the trapezoidal TWD to assess how blind people fared when approaching, locating, identifying, following along, turning at, and/or stopping and aligning at the different TWSIs based on other contextual and environmental cues in these different transportation settings. Experiment 3 is summarized in Chapter 6.

All three experiments collected both quantitative measures during each trial and participant feedback to better understand their experience using the TWSIs and navigating the different test courses. All three experiments were held in different venues: 1 and 2 at the University of North Carolina at Chapel Hill facilities, where certain aspects of the environment could be controlled, and 3 in uptown Charlotte, NC. Detailed descriptions of each setting are provided in Chapters 4, 5, and 6.

Study Participants

Potential participants with vision disabilities were identified by referral from area agencies and organizations serving people with vision disabilities. Prospective participants were interviewed by a certified orientation and mobility specialist (COMS), who served as the recruiter, using screening questions to determine prospective participants’ interest in and eligibility for inclusion. For the controlled setting experiments, the local recruiter drew candidates from the Triangle and Piedmont Triad areas in North Carolina. The natural environment setting for experiment 3 was conducted in Charlotte, so the local recruiter identified and enrolled people primarily from the Charlotte metro area.

For all three studies, participants who self-reported they were unable to ever see crosswalk lines, curbs, or poles; independently traveled (including crossing streets) at least twice a week; and had no more than moderate hearing loss or mild neuropathy were eligible. Participants varied in age (18 and older), gender, and frequency or extent of independent travel. Participants were also required to be experienced in travel using a long cane as a travel aid and willing to complete the experiment while using a long cane.

Two participants from each experiment were used to pilot-test the study, so their scores were not always included in the final analyses of data. As participants were scheduled for test sessions, they were provided a screen-reader-accessible version of the consent form via DocuSign to read and sign prior to arrival. They could also choose to have the recruiter or check-in researcher read the consent form to them and sign the form upon arriving for the study. Participants were scheduled individually for each experiment session, each of which took 1.5 to 2 hours, including reviewing and signing the consent form, familiarization with the surfaces and instructions for tasks, conducting the trials, and debriefing at the end. Participants received a $75 honorarium and reimbursement for any travel expenses getting to and from the study site for each session they participated in.