Michigan CDL - Air Brakes Practice Exam

How can you confirm that a trailer is equipped with ABS?

1. Check the tires for wear

2. Look under the trailer for wheel speed sensors

3. Inspect the trailer's exterior for ABS stickers

4. Consult the owner's manual

The correct answer is: Look under the trailer for wheel speed sensors

To confirm that a trailer is equipped with an Anti-lock Braking System (ABS), inspecting for wheel speed sensors under the trailer is the most direct method. ABS relies on these sensors to monitor the speed of each wheel, which plays a critical role in preventing wheel lock-up during braking. When the system detects that a wheel is slowing down too quickly compared to the others, it adjusts the braking pressure accordingly, which enhances vehicle control and stability. While looking for ABS stickers on the trailer's exterior can indicate the presence of an ABS system, it is not definitive. Stickers may be missing or damaged, and their presence alone does not guarantee that the system is functioning. Checking the tires for wear or consulting the owner's manual could provide related information but would not effectively confirm the installation of ABS specifically. Therefore, examining the wheel speed sensors provides the most reliable confirmation of ABS on the trailer.