Wheelman

Wheelman is a Halo 3 Multiplayer Medal awarded and achieved when the player, as the driver of a vehicle, has one of their passengers kill an opponent. The design of the medal is very similar to the Vehicular Manslaughter Medal. The Wheelman medal actually takes on the design of the Halo 2 Roadkill Medal. On the tire it says 'ROAD KILL TIRE' twice over the speakers. Usually, it is accompanied by the message, "Your driving assisted "

It can be achieved easily with any map that has a warthog, especially during big team battle games as more maps in big team have warthogs.

Trivia

 * It is in fact possible to get a Wheelman medal after someone sticks a player and then rides in a vehicle. Less common is filling someone up with Needlers or Spikes and then getting in, as the time for the projectiles to explode is minimal.Also make sure to not stop when in warthog because everyone and everything is you're enemy