The National Center on Accessibility (NCA) entered into an agreement with the U.S. Access Board and National Park Service to investigate natural firm and stable surface alternatives when creating accessible pedestrian trails, including crushed stones, packed soil, and other natural material. In some cases, natural materials may be bonded with synthetic materials to provide durable firm and stable trail surfaces. The original scope of work for this research project involved a longitudinal study that would examine the influence of five key variables: hydrology, climate, soil condition, grade and cross slope on the accessibility of trail surfaces. The project would involve the installation of 5-7 different test surfaces in various regions of the country with periodic testing and evaluation of those surfaces by local trained operators. Test plots of eleven different surface materials were installed at Bradford Woods in Martinsville Indiana. Most trail segments tested were treated with a stabilizer.

These and other conclusions are discussed in a report on the project, “National Trail Surfaces Study: Final Report,” which is available on NCA’s website