Introduction and Research Objectives

The Americans with Disabilities Act (ADA) Accessibility Guidelines currently specify that surfaces that are required to be accessible must be "stable, firm, and slip resistant" (Section 4.5.1) (USATBCB, 1992). These requirements are subjective; objective measures are not specified. These characteristics have been defined as:

  • Stability- the degree to which a surface resists change from contaminants or applied force, so that when the contaminant or force is removed, the surface returns to its original condition;
  • Firmness- the degree of surface resistance to deformation, especially by indentation or the movement of objects; and
  • Slip-resistance - the degree to which a surface provides frictional counterforce to the forces exerted in walking to permit safe ambulation (USATBCB, 1994).

Questions have arisen relating to the appropriateness and usability of various surface materials in outdoor environments required to be accessible. Additional information is necessary to provide guidance to designers and operators in order that they can provide non-discriminatory access for people with disabilities. Outdoor surface accessibility guidelines would also improve accessibility for all persons, regardless of their abilities, to a vast number of areas, including recreational facilities, playgrounds, beaches, parks, outdoor stadiums, boating and fishing docks, campgrounds, and hiking trails.

RESEARCH OBJECTIVES

The objectives of this research were to:

  1. Determine the energy costs and perceived level of difficulty to negotiate a range of outdoor surfaces among a small group of subjects with and without disabilities;
  2. Objectively measure the firmness and stability of the test surfaces;
  3. Determine the relationship between the objective surface measures, energy costs, and level of difficulty; and
  4. Propose preliminary recommendations for accessibility guidelines for the firmness and stability of exterior surfaces.