In the old days, you had to manually correct your steering in a tricky situation. Today there is ESP. ESP stands for Electronic Stability (control) Program. The name says it all - ESP stabilizes the car. Mercedes calls it ESP - other manufacturers either use their own name or it goes by ESC. Electronic Stability Control.
Should your car threaten to go into a spin, the system jumps into action almost as if an invisible hand took over to put your car back on track safe and sound. Like the Antilock Braking System (ABS) ESP helps to stabilize a car even in extreme situations. ESP's secret is an intelligent on-board computer that constantly extends its "feelers" or sensors. Whenever the danger of a spin is detected, it reacts by selectively braking the front and/or rear wheels and reducing or increasing engine torque. In a split second, much faster than a professional race-car driver could react, ESP stability control keeps the M-Class on course. The Electronic Stability Program provides an additional element of safety in crucial situations and significantly reduces the danger of skidding in turns.
Interesting additional information about ESP stability control