Bosch ESP electronic stability programme

What it is

ESP, the electronic stability programme, is a driver assistance system that helps keep a car stable and steerable when it starts to skid. Bosch developed it from its anti-lock braking system, ABS. ESP made its press debut in May 1995 in the Mercedes-Benz S-Class coupé and went on sale that September, initially as standard with the most powerful twelve-cylinder engine.

How it works

Sensors constantly compare where the driver wants to go, measured by the steering angle, with where the car is actually going, measured by a yaw-rate sensor and wheel speed sensors. If the car begins to oversteer or understeer, the system brakes individual wheels and, if necessary, reduces engine power to bring the car back on course. It works in fractions of a second, faster than a driver can react, within the limits set by physics and the grip of the tyres.

Why it stands out

ESP is one of the most important safety inventions in modern motoring. Bosch has stated that by 2020 the system had helped prevent just under half a million injury accidents and saved around 15,000 lives in the EU alone, and that it had produced more than 250 million ESP systems. Electronic stability control is now required on new cars in many markets, including the European Union. It is also a good example of German cooperation between a supplier and a car maker.

Where you meet it

Most passengers never notice ESP, except for a flashing warning light on the dashboard when the system intervenes on an icy road or in a sharp bend. It is now fitted to the vast majority of new cars and is part of the foundation for later systems such as automatic emergency braking.