Michigan State Brakes Certification Practice Exam

What is a common characteristic of most properly functioning anti-lock brake systems?

1. The brakes may lock up at any speed

2. The brakes may lock up at speeds less than 10 miles per hour

3. The system should not activate under normal conditions

4. The ABS light is always illuminated

The correct answer is: The brakes may lock up at speeds less than 10 miles per hour

The correct answer is that the brakes may lock up at speeds less than 10 miles per hour. In properly functioning anti-lock brake systems (ABS), the design is intended to prevent wheel lock-up during hard or emergency braking conditions. However, at very low speeds, particularly below 10 miles per hour, the system may not engage fully, allowing the brakes to lock if the driver applies them heavily. This characteristic acknowledges the limitations of the technology at lower speeds, where the benefits of anti-lock systems may be less pronounced. In contrast, under normal braking conditions or at higher speeds, the ABS is designed to modulate brake pressure, ensuring that the wheels do not fully lock up. This is essential for maintaining vehicle control and stability during braking. Thus, the system should not activate under normal conditions, as indicated by the reference to normal operation in the choices. The ABS light's illumination status is also not relevant to the primary function of ensuring brake safety and effectiveness during typical vehicle operation; it serves as an indicator for system health.