Boarding a vehicle that has someone driving not on your team will pop this achievement.
An easier way to grab this will be to lie prone near a vehicle in a more populated area, preferably hidden in a bush or near a building. If a vehicle spawn isn't close enough to cover or is in an open area, just drive it away a bit where you can safely hide in large brush.
Once you see someone in the area running towards the vehicle, wait until you hear the engine start, hit
, and hop on in!