A tractor-trailer combination has ABS on the tractor only, not on the trailer. How should the driver brake?

Explanation

With ABS on the tractor alone, the driver brakes no differently than usual, pressing down with whatever pressure the stop actually calls for, because ABS works automatically in the background to prevent wheel lockup and does not require the driver to change technique. 49 CFR 383.111(b)(7)(ii) directly requires CDL applicants to know about antilock brakes as part of general operating practices; the manual teaches this same normal-braking guidance regardless of which unit, tractor, trailer, or both, actually carries the ABS. Pumping the pedal rapidly is wrong because that is the old pre-ABS technique for preventing lockup, and doing it on a system already equipped with ABS can interfere with how the system responds. Braking only with the trailer hand valve is wrong because normal stops use the foot pedal, which applies both the tractor and trailer brakes together. Avoiding hard braking is wrong because having ABS on even one unit still improves control over having no ABS at all, so full, firm braking remains the correct response when needed.

Source: 49 CFR 383.111(b)(7)(ii)