Safe Driving Practices: Speed, Space, Following Distance, Braking
What this domain tests
Speed selection, following distance sized to bus length, space cushion management, and braking technique including air-brake lag and brake fade. Questions are usually situational: what speed or gap is appropriate right now.
Core rules
- The posted limit is a maximum, not a target. Slow for curves, ramps, construction, weather, and a full standing load.
- Following distance for a bus is not the car rule. At speeds under 40 mph, allow one second for every 10 feet of vehicle length; above 40 mph, add one more second.
- Stopping distance rises with the square of speed. Doubling speed roughly quadruples the distance needed to stop.
- Air brakes have lag of about half a second before pressure reaches the chambers, so look and plan further ahead than in a car.
- Brake before a curve, not in it. On long downgrades use a lower gear and snub braking, applying hard short applications rather than riding the pedal, to avoid fade.
- Buses off-track in turns; swing wide enough without crossing into oncoming lanes, and watch the mirrors through the whole turn.
- Accelerate and brake smoothly with passengers aboard; standing or seated passengers are easily thrown by abrupt inputs.
Worked example
A 45-foot motorcoach travels at 55 mph. Length gives 45 / 10 = 4.5 seconds, rounded up to 5. Because 55 mph is above 40 mph, add one second, for a 6-second following distance. At 55 mph the bus covers about 81 feet per second, so 6 seconds is roughly 484 feet. If traffic slows ahead, the driver should already be braking in that gap rather than closing it.
Traps
Using a car's three-second rule; counting the seconds starting when you decide to count rather than when the vehicle ahead passes a fixed object; ignoring air-brake lag; braking hard into a curve; riding the brakes down a grade until they fade.