Safe Driving and Operating Procedures
Safe driving starts with arithmetic. Total stopping distance is perception distance plus reaction distance plus brake-lag distance plus braking distance. At 40 mph an apparatus covers about 59 feet per second, so a 1.5-second reaction puts roughly 88 feet behind you before the brakes even apply, and air brakes add a lag of about half a second on top of that. Braking distance changes with the square of speed: doubling speed from 30 to 60 mph roughly quadruples braking distance. Weight transfer is the other physics concept to master - braking throws load onto the front axle and lightens the rear, which is why hard braking in a curve invites a spin or jackknife. Centrifugal force also rises with the square of speed, so slow down before the curve, not in it.
Understand retarders and engine brakes: useful on long descents to save service brakes from heat and fade, but never on wet, icy, or slippery pavement where they can break rear-wheel traction. ABS keeps wheels rolling so you can steer; it does not always shorten stopping distance, especially on gravel or snow - hold firm pressure and steer. Scan well ahead, use mirrors and know your blind spots, and never back without a spotter or a planned, verified path. Hydroplaning begins at lower speeds than most drivers expect with worn tires.
Traps: believing lights and siren clear traffic, trusting ABS as a cure-all, and descending grades in a high gear. Rule of thumb: descend a grade in a gear no higher than the one you would use to climb it, and if you are braking more than occasionally, you are going too fast.