Rigs of Rods is a free to play vehicle simulation with no actual objectives. The game makes use of "Advanced soft body physics" which means a use of so called beams and nodes to make up a vehicle which can bend, deform and break from collisions. Originally, the game was an offroad truck simulator (hence why that cars and non trucks are still reffered as a "truck" vehicle in the game files) until it hosted regular cars and soon, aircraft and boats. The game can be downloaded here while a repository of usermade vehicles can be found here ----