The Electronic Stability Programme fitted to the majority of modern era sports cars (also variously named DSC, MSP, PSM, CST etc), is a highly advanced system from Bosch that car makers then fine-tune to best suit the handling properties and sporting credentials of their particular cars. Operating largely through the ABS, the purpose of ESP is to constantly monitor steering wheel angle in relation to the actual direction of travel; measuring individual wheel speed, yaw angle and steering angle 25 times per second. In so doing, ESP helps compensate for driver errors that would otherwise affect lateral dynamics; whereas ABS and traction control systems (TCS) do the same for longitudinal dynamics.
If the car loses lateral traction, and either the front or rear starts to slide sideways, ESP reacts by mitigating the cause of the skid; reducing power when appropriate, and applying individual brakes as required to help force the car to follow the steering angle. In the event of understeer, ESP instantly applies the brake to the inside rear wheel to help the car rotate more, whereas if oversteer is the issue ESP triggers the outside front wheel’s brake to create a more helpful pivot point to bring the rear of the car back under control.
Clever stuff, but keep in mind that no matter how advanced the active safety systems fitted, any car remains subject to the laws of physics. Furthermore, ESP can only respond to steering angle, making it somewhat redundant if you fail to steer where you want to go. Keep in mind that your hands follow where your eyes lead, and keep looking where you want to go, your escape route, and the system will do all it can to help get you out of trouble.
Depending on the vehicle, the ESP ‘umbrella’ can also include numerous other functions to further support safety and control: Electronic Brakeforce Distribution, brake disc wiping, brake pre-fill and Emergency Brake Assist being just a few. Many tyre pressure monitoring systems also take their readings through the ESP software to avoid needing a heavy valve assembly within each wheel.