Parking a vehicle in a garage usually protects it (with exceptions noted below). The primary purpose of the garage is to allow the player to preserve vehicles that have been obtained normally, vehicles left outside are subject to disappearing after the player saves a game and restarts it later. Garages may vary both in number of spaces and height clearance (for tall vehicles such as a Barracks OL or Hotdog).
The first type is garage for storing vehicles, almost exclusively attached to a safehouse, or located near one.