People can legally make their own cars, according to Lawyers.com. In order for the car to pass safety and emissions tests, do-it-yourself car makers should check with their state's department of motor vehicles to view the necessary guidelines the car must follow.
State laws directly control the legality of vehicles, Lawyers.com states. A car's condition must be within all the guidelines of the appropriate state's laws regarding safe transportation. In order to pass state safety and emissions tests, each vehicle typically must have certain items, including a horn, a windshield and wipers, seat belts, brakes, an exhaust system and other features. Additionally, there are things that cars are not allowed to have to be considered legal. Each state has its own list of guidelines, accessible through the official department of public safety website.