Space requirements for accommodating wheeled mobility devices and their users in the built environment are key components of standards for accessible design. These requirements typically include dimensions for clear floor areas, maneuvering clearances, seat and knee clearance heights, as well as some reference dimensions on wheeled mobility device sizes. Recent research from four countries was reviewed and compared with their prevailing accessibility standards to identify needs for improving standards. Findings from ongoing anthropometry research on wheeled mobility in the U.S. were used for evaluating the adequacy of existing U.S. accessibility standards. Preliminary analysis suggests that the U.S. standards, which are based on research conducted in the 1970s, need to be updated to address advances in wheeled mobility technology and changes in user demographics. The analysis highlights the importance of integrating research with standards development, organizing international collaborations, and developing international standards. (Contains 2 tables and 8 figures.)