RESNA 26th International Annual Confence
The Americans with Disabilities Act (ADA) requires that transit providers accommodate passengers who use "common wheelchairs". Wheelchair tiedown and restraint systems (WTORS) are used to secure wheelchairs and occupants in buses. Studies have shown that improper securement is the leading cause of injury for passengers in wheelchairs. Throughout the twelve years since ADA, transit providers have complained about the usability of WTORS. This research explored the use of WTORS in actual practice, with the long-term objective of improving their usability. Ethnographic research revealed that 1) the bus operator is the key to proper securement, and 2) improper securement is both more common, and more dangerous, than previously thought.
Since the passage of the Americans with Disabilities Act (ADA) of 1990, several research projects have been done with the aim of improving the safety of wheelchair users on transit buses (1-3). While accident data for transit buses is scarce, studies indicate that the leading cause of injury among wheelchair users aboard transit buses is improper securement (1, 3).
The most common type of WTORS in use on buses is a four-strap securement system, combined with a three-point restraint system. The straps secure the wheelchair to the floor by way of S-hooks, while the restraint system is similar to the lap and shoulder belt arrangement found in passenger vehicles. Research has shown that many transit providers find the existing WTORS to be difficult to use and time-consuming (1, 4). Moreover, usability issues have remained largely unresolved in the twelve years since the passage of ADA (4).
Despite the breadth of research related to WTORS, little has been done from an industrial design perspective to improve usability. To improve the usability of any product or system, industrial designers often employ a user-centered design approach. The first step in this approach is to understand the user. Field research, a technique industrial designers are borrowing from ethnography (5), is an effective tool for "studying [users'] cognitive, behavioral, anthropometric, and attitudinal characteristics, and... the nature of the work expected to be accomplished" (6).
The long-term objective of this research was to improve the ergonomics and human factors of the existing WTORS. However, by taking a user-centered design approach, a fundamental question needed to be answered first: how are the existing WTORS used in the real world of public transportation?
We approached this study as ethnographic research, using field observation as our primary method (a supplemental focus group of bus operators was also conducted). Ethnographic research is recommended for " studying how [a culture-sharing group] developed shared patterns of behavior over time" (7), which suited our purposes quite well. Field observations were used because they would provide firsthand information about the use of WTORS in the real world.
Members of the research team rode local transit buses and observed WTORS usage, often with one researcher posing as a wheelchair user (a manual wheelchair and motorized scooter were provided for this purpose). On other occasions, a team of researchers (two or three members) rode buses while accompanied by a fellow researcher who uses a power wheelchair (and uses the bus for daily transportation). Observations were documented with digital photographs and field notes.
The information we gathered through ethnographic research could not have been captured by any other means. Surveys, interviews, and focus groups all are useful research methods, but none can reveal the actual behaviors of actual users. One example from this study may be the revelation that the bus operator is, in fact, the user of WTORS. While this seems obvious, bus operators are rarely mentioned in the literature (it must also be noted that no field observations of WTORS in use were mentioned in our review of the literature). The first step to improved usability is to identify the user, yet this research seems to be the first to do so in such a direct manner. Improved WTORS must therefore focus primarily on the needs of bus operators in order to reduce improper securement.
The improper securement scenario most often observed was later shown to be quite dangerous. Computer simulations performed by researchers at the Rehabilitation Engineering Research Center (RERC) for Wheelchair Transportation Safety at the University of Pittsburgh showed that an occupied wheelchair, secured (improperly) in this manner, is prone to tipping over during emergency driving maneuvers (braking and turning forces of 0.8g and 0.7g, respectively). By improving the design of WTORS, it seems likely that less improper securement will occur, thereby improving transit bus safety for all passengers. However, the point here is that this unsafe condition was discovered by simple observation. By simply exploring how the existing WTORS are used, a wealth of information was discovered (much of which was previously unknown).
Ironically, one of the causes for the improper use of WTORS may be the current standards that WTORS must meet. Among the many requirements of Society for Automotive Engineers (SAE) J2249, WTORS must withstand a 48-kph/20g crash, as measured by a sled impact test simulation (8). Recent studies have called into question this requirement, noting that large transit buses are very unlikely to experience such a crash (3).
The fact that current WTORS must meet this requirement has an obvious influence on their design; user needs seem to be a low-level consideration by comparison. The primary intent of the regulation is, of course, safety. In this case, however, the regulation leads to a design that is not user-friendly, and therefore used improperly much of the time. Used improperly, the WTORS will not only be ineffective in the unlikely event of a severe collision, but will also be ineffective under more typical driving conditions.
Until these standards are changed, development of a user-friendly WTORS is a more substantial challenge than it needs to be. And in the meantime, hundred--perhaps thousands--of wheelchairs are being improperly secured across the country each day.
Finally, the role of ethnographic research in all of assistive technology must be considered. As this small research study makes clear, simple field observations can uncover information unavailable in the literature, from surveys, or in interviews. How many other assistive technology "solutions" are being designed for the wrong users? Or causing injuries due to improper use? For assistive technology to be successful, designers must first know who needs assistance, and exactly what assistance is needed; ethnographic research provides the answers.
This research was funded through a Small Business Innovative Research (SBIR) grant (1R43HD39567) from the National Institute of Health (NIH). The author would like to thank the many graduate students at Arizona State University who assisted in this research, as well as Linda van Roosmalen, Ph.D. from the RERC at the University of Pittsburgh for her assistance.
Industrial Design Human Factors Research Laboratory
Arizona State University
College of Architecture and Environmental Design,
School of Design
P.O. Box 872105
Tempe, AZ 85287-2105