Lift-off oversteer (also known as snap-oversteer, trailing-throttle oversteer, throttle off oversteer, or lift-throttle oversteer) is a form of sudden oversteer occurring chiefly in rear-wheel-drive automobiles. While cornering, a driver who closes the throttle (by lifting a foot off the accelerator, hence the name), usually at a high speed, can cause such sudden deceleration that the vertical load on the tires shifts from rear to front, in a process called load transfer. This decrease in vertical load on the rear tires in turn decreases their traction by lowering their lateral force (that perpendicular to the direction of travel), making the vehicle steer more tightly into the turn. In other words, easing off the accelerator in a fast turn can cause a car's rear tires to loosen their grip so much that the driver loses control and drifts outwards, even leaving the road tailfirst. Such uncontrolled drifting should not be confused with the sport of intentionally drifting a motor vehicle. Dynamics The graphs to the right show the simulated effect of lifting off the throttle in the middle of a left turn. The transients in the first couple of seconds are due to the test, in which a step steer input (wheel angle) is applied at 0 s and held constant throughout. The steady state cornering is at constant speed, with a lateral acceleration of 0.45 g approximately until the throttle is released at 6 s. The yaw rate plot shows the oversteer due to the rear wheels losing traction - after an uncomfortable jerk at 20 deg/s, the vehicle spins sharply in the direction of the turn. The lateral acceleration also spikes to 0.6 g and levels at about 0.55 g, meaning that the radius decreased (i.e., the turn tightened). The side forces on the outside wheels increase and the inside rear (LR) wheel even lifts off the ground, a common occurrence. Snap oversteer is induced when the throttle is lifted while midway through a corner (lift-off oversteer), often by inexperienced drivers trying to reduce speed after braking too little. Moment of inertia Snap oversteer is most common with mid-mounted engine, rear-wheel-drive (MR) vehicles. Mid-mounted engine vehicles have a much lower rotational inertia than vehicles with a front-mounted or rear-mounted engine. The lower rotational inertia of mid-mounted engine vehicles causes the vehicle to spin much faster than a front or rear mounted engine vehicle. If unexpected, it can catch the driver