Hijack

The Carjacking (or Highjacker in Halo 3) Medal is awarded for stealing an occupied vehicle from an opponent. It is available in all Multiplayer gametypes where a vehicle is available and has a Bungie difficulty rating of 2 out of 10. It is represented by a cross with a U-turn sign on it. After you steal an occupied vehicle, a message appears on your screen. In Halo 2, that message reads: "You boarded an enemy vehicle", while in Halo 3, it reads: "You highjacked player's name". Also, if you hijack and commandeer a person on the back of a Warthog, you will also get an "Assassination" medal and the person will almost instantly die. If your vehicle just got hijacked, but you manage to highjack it back, you will receive the Maybe Next Time Buddy Medal.