The Design and Verification of a Pathway Measurement Tool (pathmet)

INTRODUCTION During travel over sidewalks, pedestrians encounter pathway risks that may lead to falls for all people, including manual and power wheelchair users. In fact, falls are the most common source of injury for wheelchair users [1], and the majority of these events occur during travel over poorly-maintained outdoor pathways [2]. Additionally, wheelchair users experience dangerous whole-body vibrations and the associated negative health effects, such as back pain and leg spasms, during travel over rough pathways [3]. Poorly-maintained sidewalks are an issue for walking pedestrians as well. The average person avoids thousands of trip hazards every year while walking outdoors [4]. Due to the severity of the resulting injuries, trips and falls are considered a public health risk, for they impinge on the public rights-of-way [5]. Sidewalks may be classified through a variety of properties. The United States Access Board is the governing entity that defines the standards regarding safe pathway accessibility characteristics. Such characteristics include crossand runningslope, or the degree of slope change in the sideways and forward directions, respectively. Furthermore, the Access Board defines the acceptable level change, or the maximum unevenness of congruent sidewalk. Finally, after the publication of supporting research, the Access Board is enacting standards governing sidewalk roughness, a property that depends on the material of the surface. Sidewalk accessibility is currently evaluated by an individual using a straight level, tape measure, and a sidewalk quality survey. However, there is no tool to accurately and objectively quantify sidewalk characteristics according to the Access Board standards. By identifying and correcting inaccessible sidewalks using appropriate evaluation equipment, property owners can decrease the risks to traveling pedestrians. OBJECTIVE The objective of this research was twofold. The first objective was to design PathMeT, the pathway measurement tool, a device to be used in the assessment of sidewalk accessibility according to Access Board standards. The second objective was to verify PathMeT as a reliable tool for quantifying sidewalk characteristics. HYPOTHESIS Our research team hypothesized that we could create an objective and accurate tool for quantifying surface accessibility. In essence, PathMeT would be an instrumented rolling surface profiler to measure and quantify pathway accessibility characteristics defined by the Access Board standards. The device would passively and automatically collect sidewalk properties during movement at the average walking speed of 1.0 m s ± 0.1 m s with no less than a 1 mm resolution, equating to a sampling frequency no less than 1000 Hz. PathMeT will collect data in a format compatible for processing with the Pathway Roughness Index (PRI), an algorithm that assigns a decimal number value corresponding to the perceived surface roughness. Finally, PathMeT will be reliable for all users as determined by a reliability statistical analysis with intraclass correlations greater than 0.90 and a Cronbach alpha greater than 0.95.