The handbrake turn is a driving technique used to deliberately slide a car sideways, either for the purpose of negotiating a very tight bend quickly, or for turning around well within the vehicle's own turning circle.
The driver starts by using steering input to transfer weight to the outside tyres, the handbrake is then used to lock the rear wheels, thus upsetting the adhesion between the tires and the road surface. With practice, the car can be placed accurately by releasing the handbrake and accelerating the vehicle. The technique is used in some forms of motorsport, for example rallying.
A related technique is left-foot braking.
Source: Wikipedia - en.wikipedia.org
