What is the function of the anti-lock braking system (ABS) in combination vehicles?

The function of the anti-lock braking system (ABS) in combination vehicles is to prevent wheel lock-up during heavy braking. This is crucial because when wheels lock up, the vehicle loses traction, leading to a loss of steering control. ABS works by automatically modulating brake pressure to each wheel, allowing them to continue rotating and enabling the driver to steer the vehicle even while braking firmly. This feature is particularly important in maintaining directional stability and control during emergency braking situations or in slippery conditions.

The other options do not accurately reflect the primary role of the ABS. For example, increasing fuel efficiency during braking or allowing smoother acceleration are not functions of the ABS. Similarly, while a parking brake is essential for securing a vehicle when parked, it is not managed by the ABS and operates independently. Understanding how ABS contributes to safety by enhancing braking performance and control is vital for driving combination vehicles effectively.