In the recent car teardown live stream, it was mentioned that "if you encounter danger, slamming the brakes hard is the safest method." Is this operation correct?
First, let's state the conclusion: As long as your vehicle is equipped with an Anti-lock Braking System (ABS), decisively applying full braking force (commonly referred to as "slamming the brakes") is the safest operation when encountering danger.
The driving test subject four questions already explain this: For vehicles equipped with an ABS, during emergency braking, one "can press the brake pedal firmly." And when the vehicle skids, one should also "press the brake pedal all the way down." Currently, the vast majority of passenger cars on the market are equipped with ABS, including Xiaomi Auto. When driving a vehicle equipped with ABS, "slamming the brakes" can achieve the vehicle's maximum braking effect, resulting in the shortest braking distance. At the same time, "slamming the brakes" triggers the ABS, keeping the wheels in a state between "rolling and slight sliding." This provides maximum braking force while preventing wheel lockup, avoiding loss of control due to the change from rolling friction to sliding friction between the tires and the ground, and retaining certain steering capability. During emergency braking, you can steer to avoid obstacles.
On slippery surfaces such as ice and snow, where the coefficient of friction is extremely low, the likelihood of vehicle loss of control is very high. In addition to driving slowly and maintaining a larger following distance, emergency braking requires ABS to keep the vehicle controlled during deceleration.
So why did some people previously believe that one needed to pump the brakes? Actually, "pumping the brakes" is only necessary when emergency braking in a vehicle without ABS. The purpose of pumping the brakes is to simulate the working mode of ABS by repeatedly pressing and releasing the brake pedal to prevent wheel lockup in the absence of an ABS system. However, compared to the ABS system, human limb movements are obviously much slower, and the braking effect is significantly inferior. Therefore, using the pumping motion in an emergency braking situation in a vehicle with ABS may actually extend the braking distance and increase the risk of accidents, including on slippery and icy roads.