When using ABS, stopping distance may be longer on which surfaces?

The correct answer is gravel or fresh snow because when a vehicle is equipped with Anti-lock Braking System (ABS), it works by preventing the wheels from locking up during hard braking. This is particularly useful on surfaces with good traction, like dry pavement or wet asphalt, where the system can effectively modulate braking force to maintain steering control.

However, on loose or slippery surfaces such as gravel and fresh snow, ABS may not function as effectively. This is because these surfaces do not provide consistent traction. When braking on gravel, the tires may still dig into the loose material, which can increase stopping distance. Similarly, fresh snow can create a layer of slippage that also affects how quickly a vehicle can stop, even with ABS engaged. The system's design primarily optimizes performance on solid surfaces, so it may lead to longer stopping distances on these more unstable terrains.

Understanding how ABS functions on various surfaces is crucial for safe driving practices and can help drivers anticipate their stopping capabilities under different road conditions.