MO CDL Passenger key terms

A systematic walk-around and in-cab check of a vehicle's critical parts performed before driving, intended to catch defects that could cause a breakdown, crash, or roadside inspection violation.

A written or electronic record a driver submits to the carrier describing any defect found during inspection, so the vehicle can be repaired and kept out of service until fixed.

A check made with the engine off and system charged, watching the pressure gauges for a steady drop that exceeds the allowed rate in one minute with brakes released and applied.

An audible and visual alert that must activate before air pressure falls below a set threshold, telling the driver to stop safely because braking performance is being lost.

The lever linking the brake chamber pushrod to the brake shoe; too much free travel means the brakes are out of adjustment and stopping distance increases.

A can-shaped component that converts air pressure into mechanical force to apply the service brake; a cracked housing or loose clamp band is a defect.

An emergency and parking brake held released by air pressure; if pressure is lost or the parking valve is pulled, springs apply the brakes automatically.

The measured groove depth of a tire; front tires of commercial vehicles must meet a higher minimum than other tires, and inadequate depth is an inspection defect.

Checking the tire's outer surface for cuts, bulges, exposed cords, and mismatched sizes or load ratings that would make the tire unsafe to operate.

The horseshoe-shaped coupling plate on a tractor that locks onto the trailer kingpin; it must be greased, undamaged, and securely latched before towing.

The vertical pin under the trailer nose that the fifth wheel jaws grip; a bent, worn, or poorly seated kingpin can let the trailer separate from the tractor.

The retractable legs supporting a parked trailer; they must be fully raised and secured before moving, with no cracks or missing parts.

The hoses and cable connecting tractor to trailer; they must be properly coupled, free of leaks or chafing, and supported so they do not drag or disconnect.

Verifying that passenger doors, roof hatches, and window exits open freely, are labeled, and have functioning alarms or buzzers where required.

The main boarding door of a bus; it must open and close smoothly, latch securely, and have a working emergency release and warning device.

A floor marking showing where standing passengers may not cross, keeping the aisle and driver's area clear and preserving the vehicle's weight distribution.

The requirement that riders be seated or standing within allowed areas while the bus is moving, and that mobility devices and cargo be fastened so they cannot shift.

The scored off-road portion of the CDL skills test in which the driver demonstrates precise low-speed maneuvering in a controlled lot with cones and marked boundaries.

A basic control skill requiring the driver to move forward and stop with the front bumper within a marked zone, without touching boundary lines or cones.

Backing the vehicle in a straight path inside a narrow lane while using mirrors and reference points, stopping within the marked end zone.

A maneuver in which the driver backs from an alley into a simulated dock space, using pull-ups as allowed, without striking cones or crossing lines.

Backing into a space that is not directly behind the vehicle, requiring the driver to judge angles and pivot points while staying inside the marked area.

A basic control skill where the driver parks the vehicle alongside a simulated curb between barriers, finishing close to the boundary without touching it.

A visible feature on the vehicle or ground that the driver uses to judge position and clearance when mirrors alone do not show exactly where the tires are.

A permitted forward correction during a backing maneuver; the number allowed is limited, and exceeding it or leaving the boundary costs points.

The scored public-road portion of the CDL skills test evaluating lane control, turns, intersections, speed management, and interaction with traffic.

A maneuver requiring mirror checks, a head check of the blind spot, a signal, and a smooth move only when space and speed allow it safely.

The gap kept behind the vehicle ahead; at highway speed it should be at least one second per ten feet of vehicle length plus a safety margin.

The safety margin kept around the vehicle on all sides so there is room to stop or steer away if traffic ahead or beside suddenly changes.

Slowing, checking tracks in both directions, listening, and crossing only when there is room on the far side, with hazard lights used as required.

The outward drift of a long vehicle's rear end during a right turn; the driver must check the right mirror and may need to swing left first to clear the curb.

The tendency of the rear wheels of a long vehicle to follow a tighter path than the front wheels, which can cause the trailer to strike curbs or vehicles.

A commercial license for operating a single vehicle with a gross vehicle weight rating over 26,000 pounds, or such a vehicle towing a trailer of 10,000 pounds or less.

A commercial license for smaller commercial vehicles designed to carry 16 or more passengers, or to haul hazardous materials requiring placards.

The P endorsement added to a CDL that authorizes driving a commercial vehicle carrying passengers, requiring a separate knowledge test and skills test in a bus.

The driver's responsibility for boarding, seating, and behavior of riders, including refusing to proceed when the bus is unsafe or passengers are unruly.

A prohibition on operating a vehicle or driver found in serious violation during an inspection; operating in violation carries heavy penalties.

Federal limits on driving and on-duty time for commercial drivers, including required rest breaks and limits on consecutive driving hours.