Restricted vs. unrestricted space for L-turns: A debate in environmental design

Wheeled mobility device users face challenges in terms of access to the built environment and maneuverability within the built environment has received limited attention. As the wheeled mobility device user population has changed drastically in the recent years, there is a need to update accessibility standards and develop reliable methods for testing user performance in the built environment. This paper presents a comparison of restricted and unrestricted space requirements for angle turns (L-turns) with the aim of highlighting differences between space requirements in these situations and comparing the results to current accessibility standards. One hundred forty wheeled mobility device users completed L-turns to the best of their ability in a restricted space environment, and thirteen performed the same maneuver in an unrestricted space environment. Data indicates that although entrance dimensions of the turns are similar between the restricted space and unrestricted space groups, there is a significant difference between exit dimensions. This suggests that when unrestricted space is utilized, users may adopt different strategies and paths when executing their turns. Additionally, a comparison of the study results, both in the restricted and unrestricted conditions, to current accessibility standards indicates that a large proportion of individuals may not be able to successfully complete L-turns in compliant built environments. In the design of the built environment, researchers and designers should consider space requirements, ease of execution and time of execution simultaneously to create comfortable and accessible environments for normal and urgent circumstances.