Hill-Start Assist is a feature that takes advantage of drive-by-wire braking technologies. Where a manual brake needs very careful driving to ensure you don’t roll back down an incline, an electronic system, like autonomous emergency braking (AEB) or anti-lock braking system (ABS) will use the car’s computer to improve safety. The car holds the position and applies the brakes until you’re ready to move off.
How does it work?
Traditionally, as you are preparing to drive off on a gradient, you have to find the clutch biting-point and, upon feeling that, release the handbrake and drive forwards, up the incline.
If the driver judges the clutch bite incorrectly, the car will respond by lurching forwards or, potentially more seriously, rolling backwards. If there is traffic behind the car, such a response could cause unwanted problems on your journey.
Hill-start assist works by sensing the car is on an incline and holding the brakes for a few seconds, even after the handbrake has been released. In these precious nanoseconds, the clutch’s biting point is found and the car can move forwards with no risk of rolling back.
Generally, a hill start in a car with an automatic gearbox is easier because the vehicle controls the automatic clutch or torque converter already. This allows the driver to move away at the optimum point simply by controlling the accelerator.
Do I need it?
It’s a feature few drivers need, but since it reduces the risk of an accident, it makes hill starts safer.
As it’s a reasonably inexpensive technology, inevitably an increased number of new cars come fitted with hill-start assist.
Models fitted with electronic parking brakes ensure that all the driver has to do is begin the process of driving off on a hill is find the clutch’s biting point and drive away. The brake and hill start assist automatically disengaging at the same time.
Some cars – VW Group vehicles in particular have a very effective system – feature an additional Auto Hold system for the brakes. By simply prodding firmly on the brake pedal when the driver comes to a standstill, the electronic parking brake – and consequently the hill-start assist – are automatically engaged.
Almost every manufacturer produces cars with hill-start assist, either as standard or as an extra-cost option.