What does the antilock brake system monitor to prevent skidding?

The antilock brake system (ABS) is designed to enhance vehicle safety by preventing wheel lock-up during emergency braking situations. It achieves this by continuously monitoring several critical factors: wheel speed, brake pedal position, and brake pressure.

Monitoring wheel speed allows the ABS to detect when a wheel is about to lock up due to excessive braking force. If one or more wheels are found to be slowing down significantly faster than others, this indicates potential skidding. The system then modulates brake pressure to those wheels, reducing the force applied in a controlled manner to prevent lock-up and maintain steering control.

The brake pedal position is monitored to determine how hard the driver is pressing the brakes, which helps the system react appropriately in managing brake pressure. Finally, monitoring brake pressure itself allows the system to make real-time adjustments to the braking force being applied, ensuring that the wheels maintain optimal traction with the road surface.

Together, these monitored parameters enable the ABS to effectively prevent skidding and help maintain vehicle stability during braking, especially in slippery conditions. Other options like brake fluid levels, brake pad wear, and engine temperature do not provide the necessary data for the ABS to function, as they do not directly relate to the braking dynamics that cause skidding.