OR CDL School Bus key terms

A systematic walk-around check of lights, tires, brakes, fluids, mirrors, and emergency equipment performed before driving. The driver must confirm each item is present, secure, and working, and correct or report defects before the vehicle moves.

A static check with the engine off and system fully charged. With the service brake applied, leakage must stay within the limits in the CDL manual; excessive loss means the vehicle is unsafe to drive until repaired.

A check that the air system holds pressure with the engine off and brakes released. Any steady drop indicates a leak in the compressor, lines, or valves that must be found and fixed before operation.

A buzzer and light that activate when air pressure drops below the threshold set in the CDL manual, typically around 60 psi. The driver must stop safely and never continue driving with the warning active.

A parking and emergency brake held engaged by a powerful spring and released by air pressure. If air pressure is lost, the spring applies the brake automatically, which is why a pressurized system is required to move.

The pressure at which the compressor stops pumping, commonly about 125 psi, and the cut-in pressure where it restarts. Knowing the normal range helps the driver spot a failing compressor or governor during inspection.

A test that the parking brake holds the vehicle when applied and releases fully when air pressure builds. On air brake buses, the driver confirms the spring brakes engage and disengage with a clear audible release.

The lever that links the brake chamber pushrod to the brake shoe. Too much pushrod travel means poor braking, so the driver checks travel during inspection. Excessive travel is a defect that must be corrected before driving.

A measurement of brake chamber pushrod travel to confirm the brakes are properly adjusted. The acceptable limit depends on chamber type and size, and a reading beyond the limit means the vehicle is out of service.

An inspection for cracked, frayed, or glazed belts and for hoses that are leaking, swollen, or rubbing. These defects can cause loss of cooling, charging, or air pressure while the bus is on the road.

Verifying engine coolant is at the correct level in a properly pressurized system, with the engine cool. Low coolant risks overheating and engine damage, and opening a hot system can cause severe burns.

Confirming that every emergency door, window, roof hatch, and exit is unobstructed, marked, and opens freely from inside. The driver also verifies the audible warning works when an emergency exit is opened.

Checking each tire for minimum tread depth, cuts, bulges, exposed cords, and proper inflation. A bus tire with a defect such as a bulge or exposed cord is unsafe and must be replaced before passengers are carried.

Looking for cracked rims, missing or loose lug nuts, rust streaks, and oil leaks at the hub. These signs can indicate a wheel about to fail, which is a critical defect on a passenger-carrying vehicle.

A written record of defects found during the pre-trip or post-trip inspection. The driver signs and submits it so the carrier can repair items, and defects affecting safety must be corrected before the bus is used again.

A walk-through after the run to look for defects, mechanical problems, and items left on the bus, including sleeping or left-behind passengers. Findings are recorded on a report so repairs can be made before the next trip.

Setting flat and convex mirrors so the driver can see the sides and rear of the bus, including blind spots near the wheels. Proper adjustment must be done before moving and checked after any seat change.

An area around the bus the driver cannot see in the mirrors or directly. Large blind spots exist directly in front, behind, and along both sides, so the driver must scan and use mirror checks before any turn or lane change.

A quick look over the shoulder to confirm no vehicle, cyclist, or pedestrian is in a blind spot before changing lanes or pulling out. Mirrors alone are not enough on a large bus.

The space kept behind the vehicle ahead, measured in seconds by counting as that vehicle passes a fixed object. Buses need extra space for stopping distance and should increase it in rain, snow, darkness, or heavy traffic.

The safety margin kept around the bus on all sides. Managing it means avoiding tailgaters, leaving room ahead, and choosing lanes that allow escape routes if traffic stops suddenly.

The total distance traveled from the moment a hazard appears until the bus stops. It combines perception, reaction, and braking distance, and grows with speed, weight, and slippery road conditions.

Loss of braking power caused by overheating drums or shoes after repeated or prolonged braking, such as on a long downgrade. The driver should use a lower gear and controlled braking to prevent it.

Using a lower gear so the engine slows the bus on descents instead of relying only on the brakes. This helps control speed and reduces heat buildup on long downgrades.

Changing to a lower gear to gain engine braking or power on a grade. The driver should select the gear before the descent begins and avoid coasting in neutral, which reduces control.

The steps taken at every crossing: slow down, turn off noisy devices, open the window to listen, look both ways, and proceed only when the tracks are clear. A bus must never stop on the tracks.

The sequence for loading and unloading: signal, stop in a safe position, set the parking brake, place the transmission in neutral or park, and account for students before moving. Students must cross only on the driver's signal.

The area immediately around a school bus where children are hardest to see, roughly ten feet in every direction. The driver must account for every student leaving and re-entering this zone before moving the bus.

A required end-of-run walk through the bus to confirm no child remains asleep or hidden on board. The driver physically checks under seats and in the back before securing the vehicle.

A practice exercise in which riders learn to leave the bus quickly through doors, windows, and roof hatches. The driver assigns helpers, explains exits, and keeps everyone calm and clear of traffic.

Removing passengers from a bus during fire, crash, or other danger. The driver secures the vehicle, directs students to a safe gathering point away from traffic, and accounts for everyone before leaving the scene.

A passenger who rides while standing, allowed only where the bus is designed and permitted for it. The driver must start and stop smoothly and keep standees behind the standee line.

A marking on the floor showing where standing passengers may not pass toward the driver. Keeping the aisle and front area clear protects the driver's view and control of the bus.

Keeping the walkway free of bags, feet, and equipment so passengers can move to exits quickly. Blocked aisles slow evacuation and can cause falls when the bus stops or turns.

The short instructions given before departure covering seat belts where required, emergency exits, and rules for a safe ride. Clear briefing helps passengers act correctly if an emergency occurs.

Any activity that takes attention from the road, such as phone use, eating, or managing passengers. On a school bus the driver must stay focused and handle student issues only when the bus is stopped safely.

Flashing warning lights used to alert other drivers when the bus is stopped, disabled, or moving slowly. They are not a substitute for proper signaling and should be turned off before normal driving resumes.

A sequence confirming the service brake, parking brake, and air system work before departure. The driver checks for leaks, warning devices, and that the bus does not roll when the brake is applied.