During hard braking, when is the greatest usable braking force available?
Correct answer: B – When maximum braking is applied without allowing the wheels to lock
Locked wheels have less traction than rolling wheels and may cause a skid or spinout. Controlled braking applies the brakes as firmly as possible without wheel lockup. ABS similarly adjusts brake pressure to provide strong braking while helping prevent the wheels from locking and preserving vehicle control.
Source: Texas Commercial Motor Vehicle Drivers Handbook — § 2.17.2, “How to Stop Quickly and Safely”; § 2.18.4, “How ABS Helps You”

