Anthropometry of Wheeled Mobility Project: Final Report

4.3.5.1 90-Degree Turn

This turning clearance is applicable for exterior and interior circulation, aisles in seating areas, ramps and other locations. The width of circulation spaces should be wider to accommodate two-way traffic and egress requirements.

The mean values for scooters in our sample are in excess of the current standards. In addition, less than 80% of power and manual wheelchair users in our sample are accommodated by the standard. We recommend revising the ADA-ABA standard for 90-degree turning width to 1000 mm (39 in.) which would accommodate at least 95% of our sample. Figure 4‒4 shows the accommodation model of the minimum clear width required for the 90-degree turn.

Figure 4-4: Accommodation model depicting the minimum clear width required by users of manual wheelchairs, powered wheelchairs and scooters to complete a 90-degree turn.

Long Description: This data depicts the amount of space required by users of wheeled mobility devices to perform a 90-degree turn ("L-Turn"). The bold dashed line in the table and figure indicates the current ADA requirement of a 91.5 cm (36 in.) passage width. Findings from the Anthropometry of Wheeled Mobility Study indicate that a width of at least 85 cm (33 in.) was required for 50% of the manual and power wheelchair users measured in this study to perform a 90-degree turn. A width of 100 cm (39 in.) was required in order for 95% of manual wheelchair and power chair users to complete the turn, with 95% of scooter users needing a width of at least 110 cm (43 in.) These data are based on measurements of wheeled mobility users performing 90-degree turns in a hallway, built with mock walls. The outside wall of the hallway was fixed. The other side of each leg had moveable walls. The enclosed space was incrementally increased until a user could pass through the turn successfully. The minimum space required for completing a 90-degree turn within moving or knocking down any of the walls was recorded. Use of multiple short turns was allowed in contrast to a single continuous turn.