Anthropometry of Wheeled Mobility Project: Final Report

1.0 Background

Relevance

The standards used to ensure accessibility for people who use wheeled mobility devices (WhMDs) like wheelchairs and scooters are based on research in anthropometry, the measurement of body sizes and physical abilities. The anthropometric data on WhMD users that underlies the technical requirements of the ICC/ANSI A117.1 (1998) Accessible and Usable Buildings and Facilities (ICC/ANSI) were generated from research completed from 1974 −1978 using a research sample that included about 60 individuals who used wheelchairs (see Steinfeld et al., 1979). In 1982, the U.S. Access Board developed the first Federal guidelines for facility accessibility in the U.S. Under the Americans with Disabilities Act of 1990 (ADA), the Board continued this work, publishing the ADA Accessibility Guidelines (ADAAG) in 1991, which were updated in 2004 by the ADA and ABA Accessibility Guidelines for Buildings and Facilities (ADA-ABA Standards). The latter was adopted in place of the ADAAG by the Department of Justice in 2010. Provisions for WhMD users in both guidelines were largely derived from the research conducted in the 1970’s (Steinfeld et al., 1979). Comments from people who use powered mobility devices indicate that increases in space and maneuvering requirements and decreases in reach ranges are needed in the Board’s guidelines to accommodate the use of such devices, which are generally larger, heavier, and less finely maneuverable than manual wheelchairs. Since the 1970’s, research on the anthropometry of WhMD users has been conducted in Australia, the United Kingdom (U.K.) and Canada. All of those countries have revised or are revising their standards based on that research.

In 30 years, many changes have occurred in nature of the U.S. population, the characteristics of people who use WhMDs and the characteristics of equipment that they use. Many more power chairs are in use now than in the 1970’s. Significant advances in wheeled mobility technology,health care, public health and demography have occurred that impact the body sizes and functional abilities of those who use wheeled devices for mobility. For example, power wheelchairs and scooters are often larger in size than manual chairs. In addition, improved health care technology has allowed people with more serious disabilities to survive longer than in earlier decades. These individuals may have conditions that affect their abilities to maneuver devices in small spaces or reach objects. A significantly broader range of devices is now available, from highly-adjustable battery-powered wheelchairs to 3- and 4-wheeled scooters with front tillers. Anthropometry of Wheeled Mobility Scooters also are growing in popularity. Yet, the technical requirements in U.S. standards have not changed. It is likely that the current U.S. standards do not reflect the actual dimensions and abilities of contemporary WhMD users.

Very few studies of the anthropometry of WhMD users were conducted in the 1980s and 1990s, especially in the U.S. In response to this lack of current information, the IDeA Center, with funding from the National Institute on Disability and Rehabilitation Research, developed a new set of anthropometric measurement methods and a comprehensive anthropometric data set of over 200 WhMD users was created (Feathers et al., 2002, 2004; Paquet and Feathers, 2004; Steinfeld et al., 2005). Rigorous scientific procedures were used in the development of the research methods and new software was created to organize and analyze the results. While much was accomplished in that study, there were important research needs that were unmet. First, a larger sample was needed to provide a more accurate characterization of the anthropometry of WhMD users. Second, a more diverse sample in terms of ages and WhMD technologies was needed to help improve the representativeness of the sample. Third, new dissemination products were needed to help ensure that the research findings could be translated to design practice and standards development.

Additionally, comparisons of international standards and research were needed to assess the adequacy of the current U.S. accessibility standards and help set priorities for improving regulations. Comparisons are also useful to identify best practices and differences related to cultural factors. Thus, in addition to collecting anthropometric data, we also completed a comparative analysis of research and standards on wheeled mobility in the U.S., the U.K., Australia and Canada. The analysis was limited to WhMD dimensions, minimum clear floor areas, space requirements for maneuvering, knee and toe clearances, and reach limits.

Objectives

The objectives of this study, supported by the U.S. Access Board were to:

1. Collect data on an extended sample with a target of a total of 500 individuals.

2. Collect and compare anthropometric research studies on wheeled mobility in Canada, the U.K. and Australia, with the U.S. standards and the research results from the current study.

3. Develop dissemination products including a final research report, tools for using the database and an online educational module.

The scope of the research analysis was limited to key anthropometric issues in accessibility standards:

• Unoccupied device width and length

• Clear floor space, or occupied footprint

• Seat height*

• Knee and toe clearances:

  • Knee height and depth

  • Toe height and depth

• Maneuvering clearances on level surfaces:

  • 90-degree turn

  • 180-degree turn

  • 180-degree turn around a barrier*

  • 360-degree turn

• Reach ranges:

  • Forward reach

  • Side reach

  • Side reach over an obstruction

• Grip Forces*

• Door use

Note, scope items with asterisks were added by IDeA Center.

Report Organization

This report documents the basic findings of the research and compares them to the national standards from the three countries and the U.S. It also compares the research findings to the research underlying the standards of these three other countries. Section 2.0 describes the methods we used to collect the data and make the comparisons. Section 3.0 describes the research results. Section 4.0 discusses the implications of these findings for design and standards development. Section 5.0 describes related dissemination and knowledge translation activities, and Section 6.0 provides some general conclusions, including recommendations for future research and knowledge translation activities. The Appendix includes a list of publications on the project and a set of information tools for designers and standards makers.

Units

The scientific practice of anthropometry is conducted using Metric units. However, in the U.S., accessibility standards are developed in Imperial units. Thus, in this report, we have used Metric units as the primary form for all dimensions. Some tables only have Metric units for space reasons. We included Imperial equivalents in parentheses in the text to assist the reader who is familiar with the dimensions in the standards. The ADA-ABA and other U.S. standards use a “soft’ conversion method in which Metric equivalents are rounded off to the nearest 5 mm except for very small values. Thus, in this report, where we refer to values in the ADA-ABA, we use the soft conversion to avoid confusion with the original source. Elsewhere, including our recommendations for revising the ADA-ABA, we use a “hard” conversion, rounded off to the nearest 1 mm. One exception to the Metric units as primary is in Section 3.0 on grip forces, and these dimensions are reported in pounds-force (lbf) as they were collected.

Text Descriptions

To facilitate comprehension of the report by people who use screen readers, we have included descriptive captions for all figures and tables, alt tags in digital versions and long text descriptions for figures. In Section 3.0, there are graphs of results but, each graph is simply a graphic summary of the data in the accompanying table that appears below it. The tables are readable by screen readers. Thus, there is no need for a further text description of the summary figure since the data is fully accessible to all readers.