The Americans with Disabilities Act (ADA) 1990 includes a provision requiring that new construction and alterations to existing facilities comply with the ADA Standards for Accessible Design. This report explains 23 common accessibility errors or omissions that the Department of Justice has identified during the course of its enforcement efforts. Each error/omission addresses the specific point of failure, the probable result of the error, and the ADA requirement that has been violated. Also, the text includes references to figures found in the Standards for Accessible Design. Topics cover concerns such as parking specifications, stairs and doors, bathroom accessibility, drinking fountains, and lodging accommodations. (CMD)