Which braking technique should be avoided on slippery surfaces when driving a school bus?

Stab braking is a technique that involves applying the brakes firmly and then releasing them to regain traction. This method is typically used to stop quickly without allowing the wheels to lock up on dry surfaces. However, on slippery surfaces, such as those covered in ice or snow, this technique can lead to the wheels locking up and a loss of control over the vehicle. Consequently, stab braking should be avoided on such surfaces because it can increase the risk of skidding and make it difficult to steer the bus effectively in the desired direction.

In contrast, other techniques like engine braking, light pressure braking, and even hard braking (when done carefully) can help maintain better control of the vehicle on slippery roads. Engine braking uses the vehicle's own power to slow down, allowing for smoother deceleration without the abrupt stopping power that stab braking employs. Light pressure braking gently decelerates the bus, helping to maintain traction. Even though hard braking can be effective, it should be used with caution on slippery surfaces to prevent losing control. Thus, stab braking is singled out as the technique to avoid in these conditions.