The description says it all. Win 10
ranked Banklot Battles in a row - loose your streak and you'll have to start from scratch.
You can save some time by going for these two achievements at the same time;
The Trooper achievement in Stuntman: Ignition worth 142 pointsFinish in 1st place with each of the vehicles in Backlot Battle Don't take turns in winning
Change vehicle between races
Don't hit each other