There are two ways for Wei to get access to a vehicle in Sleeping Dogs, either by stealing it or by use of the garages. Wei can steal any vehicle he comes across in his travels, by either walking up to it or by performing an Action Jack.
ACTION JACK
While Wei is driving, he is able to jack any car in front of him by holding down the appropriate button, which will make Wei open the door and climb halfway out of the vehicle. As he gets closer to the car he wants to jack, an arrow will appear and when it's green, he can press the same button to jump onto the vehicle and steal it. For larger vehicles, like trucks, he will need to shimmy to the driver's side door to successfully steal it.
GARAGES
As Wei pushes through the story and side missions, he will gain access to vehicles that are unlocked. These vehicles are stored in a garage, which he can always access right outside of a safehouse. After a certain story mission, Wei will gain the ability to buy vehicles from certain NPCs, thus unlocking more options for vehicles. Once Wei gets to a certain Face Level, he can have a valet bring any unlocked car to him, at any place where he is without needing to use a garage.
