The latest generation of the Electronic Stability Program ESP® makes a convincing impression with its even more precise and finely controlled interventions. This technology is fitted as standard in the new A-Class and is underpinned by a control unit which also contains the functions of the anti-lock braking system, acceleration skid control and Brake Assist. ESP® improves a car’s directional stability and reduces the danger of skidding under braking or acceleration or when coasting freely, by braking each wheel individually and/or adjusting the engine torque. The system also helps to shorten the ABS braking distance through corners and on roads where one side is slippery.

The hydraulic unit and electronic control module of the new generation of ESP® form a single compact unit. This means that the latest ESP® technology takes up around a third less space than its predecessor and also stands out with its lower weight. An-other new feature is the active wheel speed sensors, which are each equipped with a separate voltage supply and feed the ESP® computer even more precise data. A cen-tral point of this innovative system is the micromechanical rotational speed sensor, which records the movement of the vehicle around its vertical axis and thus recog-nises skidding movements. This sensor is located in the tunnel trim next to the park-ing brake lever and transmits its data via a separate databus system to the ESP® control unit.

For the new A-Class, Mercedes-Benz has dispensed with the button on the dashboard which allowed the driver to deactivate the acceleration skid control system. The new, intelligent control logic of the Stability Program uses data from sensors to recognise situations on the road where this function is required and automatically adapts the skid control function accordingly.

As before, the A-Class comes with the hydraulic Brake Assist system, which offers particularly notable advantages for compact cars with front-wheel drive. Where Brake Assist was previously linked up to a brake booster, the system now uses the ESP® infrastructure, making it more compact, lighter and more effective. The Brake Assist function is controlled by the high-pressure pump in the ESP® hydraulic unit. In emergency braking situations, this pump assists the driver by generating maximum pressure of 200 bar and thus helping to reduce the stopping distance. The necessary information is supplied by the wheel speed sensors, the stop lamp switch and two pressure sensors in the hydraulic unit.