Why braking during a skid is outdated (and dangerous) advice – Jalopnik

If you learned to drive before anti-lock braking systems (ABS) became common, or if you were taught to drive by someone who did, you probably received driving advice such as: “pump your brakes to avoid locking and losing traction during a skid.” Although some cars were ahead of their time, ABS did not become common in most vehicle versions until the 1990s. Without ABS, pressing the brake pedal as soon as the tires lost traction left them locked with no chance to regain control on slippery surfaces. Braking gently gave the tires a chance to regain grip between braking.

However, when performing an emergency stop in a vehicle equipped with ABS, you must maintain firm pressure on the brake pedal with your right foot until you have stopped or are ready to continue driving. Contrary to the advice given to avoid skidding on vehicles without ABS, pressing the brake pedal on an ABS-equipped vehicle can disable the system, increasing the braking distance.

Modern cars combine ABS with traction control, making pumping the brake pedal an outdated and sometimes dangerous way to maintain control during a skid. Although traction control can be an annoyance in some cars, it has been proven that when combined with ABS, it reduces the risk of accidents.

Anti-lock braking systems use sensors on each wheel to monitor tire speed. The vehicle’s computer monitors the speed data provided by the sensors, in addition to other data such as braking force and vehicle speed. The system activates when the brakes are applied and the wheel speed does not match the vehicle speed. The rapid deceleration that occurs just before the brakes lock is counteracted by the system opening a valve to relieve brake line pressure to that wheel. If the brakes are still applied, the valve closes and a pump quickly reapplies brake pressure. The process repeats until the danger of locking the brakes has passed or the brake pedal is released.

In vehicles equipped with ABS, the system essentially pumps the brake pedal for you to prevent the brakes from locking up, but it does so much faster and more accurately than any human is capable of doing. You may feel or even hear the system vibrate through the brake pedal. However, it is important to recognize the feeling as a normal indication that the system is working properly.