On a vehicle with anti-lock braking systems (ABS), what should the driver do during hard braking?

With ABS (Anti-lock Braking System), during hard/emergency braking the driver should apply FIRM, STEADY pressure and let the ABS do its job — the ABS automatically prevents the wheels from LOCKING UP (which would cause skidding and loss of steering control). CDL air brakes. DO NOT PUMP the brakes with ABS — pumping interferes with the system; just hold steady pressure. ABS helps you maintain STEERING CONTROL and a straight stopping path during hard braking, especially on slippery surfaces. ABS does NOT necessarily shorten stopping distance — its benefit is preventing skids and keeping the vehicle controllable. If the ABS warning light is on, the ABS may not be working (the regular brakes still function). Knowing to apply steady pressure (not pump) with ABS is commonly tested.