Hill-Start Assist
Hill-start assist (HSA) briefly holds brake pressure when the driver moves from the brake to the accelerator on an incline. Its purpose is to reduce unintended rollback or forward roll while the vehicle starts moving.
What it does
The system identifies the slope and whether the vehicle is stationary, then keeps the brakes applied for a short time after the pedal is released. Brake pressure normally releases when sufficient drive torque is available or when the hold period expires. Operation, supported directions, slope threshold, and hold time vary.
HSA is not the same as an automatic-hold function, which can keep the vehicle stopped for a longer period in ordinary traffic. It also does not guarantee that the vehicle will remain still on every surface or gradient. The driver must apply the brake again if the vehicle starts to move unexpectedly.
For the shared brake-control hardware and stability functions, see Electronic Stability Control.