Commercial Driver License (CDL) Class B Practice Test

How can you identify whether your vehicle has antilock brakes?

1. By the size of the tires

2. They will have yellow malfunction lamps on the instrument panels

3. By the weight of the vehicle

4. By the color of the brake fluid

The correct answer is: They will have yellow malfunction lamps on the instrument panels

Vehicles equipped with antilock brakes (ABS) will have a yellow malfunction lamp on the instrument panel. This indicator serves two key purposes: it alerts the driver that the vehicle has antilock braking technology installed, and it also shows if there is a problem with the ABS system itself. When the vehicle's ignition is turned on, the ABS light may illuminate briefly as a part of the self-test process. If the light remains on while driving, it signals that there may be an issue that needs attention. The other options do not reliably indicate the presence of antilock brakes. Tire size is unrelated to whether a vehicle has ABS, and the weight of the vehicle does not provide any clear information about the braking system. Furthermore, the color of the brake fluid does not correlate to the vehicle's braking technology—it is standard across different systems and does not indicate whether ABS is present or functioning.