Commercial Driver License (CDL) Class B Practice Test

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Study for the Commercial Driver License (CDL) Class B Test. Study using multiple-choice questions, hints, and explanations. Prepare for your exam effectively!

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What is the main purpose of the ABS on a tractor-trailer?

  1. To provide extra power

  2. To prevent wheel lock-up during braking

  3. To assist in steering

  4. To increase cargo space

The correct answer is: To prevent wheel lock-up during braking

The main purpose of the Anti-lock Braking System (ABS) on a tractor-trailer is to prevent wheel lock-up during braking. When brakes are applied hard, the wheels can lock up and cause a loss of traction, leading to a skid. ABS allows the wheels to continue to rotate by modulating brake pressure, which helps maintain steering control and stabilizes the vehicle during emergency stops. This becomes crucial, especially in adverse weather conditions where skidding is more likely. The other options do not align with the function of ABS; it does not provide extra power, assist in steering, or increase cargo space. Each of these features plays a different role in vehicle operation, but they are not related to the braking function that ABS primarily addresses.

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