Vehicle Controls, Braking, and Space Management
This domain tests smooth control of a heavy passenger vehicle, correct braking technique, and following distance. The examiner is looking for the CDL space formula and for decisions that protect standing passengers.
Controls and braking
Know the air brake system if equipped: check the low-pressure warning, spring brakes, and brake adjustment during the pre-trip. Brake early and smoothly; hard braking can throw standees and seated passengers. On long downgrades, use a lower gear or retarder and avoid riding the brakes, which can cause fade. Use ABS as designed: maintain steering and brake pressure during a hard stop.
Space management
Look 12 to 15 seconds ahead. Use at least one second of following distance for each 10 feet of vehicle length below 40 mph, and add one second above 40 mph. A 40-foot bus therefore needs 4 seconds below 40 mph and 5 seconds above 40 mph. Increase that cushion at night, in rain, or when passengers are standing.
Worked example
You drive a 40-foot bus at 45 mph on dry pavement. The base following distance is 5 seconds: 4 seconds for length plus 1 second because you are above 40 mph. In rain, add more space and slow down; the formula is a minimum, not a target.
Traps
Using a car’s 2-second gap; braking late; coasting in neutral; forgetting tail swing when turning; and assuming a heavy bus always stops shorter.