Section 37.3 of the DOT's regulations implementing the Americans with Disabilities Act of 1990 (ADA) (49 CFR Parts 27, 37, and 38) defines a "common wheelchair" as a mobility aid belonging to any class of three or four-wheeled devices, usable indoors, designed for and used by individuals with mobility impairments, whether operated manually or powered. A "common wheelchair" does not exceed 30 inches in width and 48 inches in length measured two inches above the ground, and does not weigh more than 600 pounds when occupied. If an electric scooter or other mobility device meets the physical specifications of a common wheelchair as defined by the DOT's ADA regulations, it must be treated as a common wheelchair.