There is 1 way to get this achievement:- Quad Bike Roadkill
You will need to find a quad bike, and they are littered all over the new Armoured Kill DLC maps, and your best bet is probably to play Conquest mode. It looks like an ATV. Once you are on the bike, try to catch an enemy that is by themselves from behind, at a fast speed, killing them and unlocking the achievement. Cycle trough 1st and 3rd person view by clicking the Right Stick.
- AT Mine Kills, while seated on bike
(No longer works)
Another method is to plant AT mines on a busy street, then seat yourself on a Quad Bike, in a corner of the map, and wait for your AT mines to kill enemy players. If you get a kill while seated on the bike (from your mines) you will unlock the achievement.