Hawaii CDL General Knowledge key terms

A systematic walk-around check of a commercial vehicle before driving, covering lights, tires, brakes, coupling devices, fluids, and emergency equipment, intended to catch defects that could cause a breakdown or crash.

A written record completed after each pre-trip or post-trip inspection that lists any defects found and the signature of the person certifying the inspection was performed.

The carrier's form on which a driver records vehicle defects and a mechanic notes repairs; a driver must review it before operating a vehicle and must not drive until listed safety defects are corrected.

The minimum legal tread measured in the major grooves: 4/32 inch on front steer tires and 2/32 inch on all other tires of a commercial vehicle.

Cuts, bulges, or exposed cord on a tire's side surface that make the tire unsafe; a driver must not operate a vehicle with such damage.

A check with the engine off and system charged where the driver watches the gauge for pressure loss with brakes released and then applied, verifying the system holds air within allowable limits.

The pressure settings at which the compressor resumes pumping (cut-in, roughly 100 psi) and stops pumping (cut-out, roughly 125 psi) to keep the air system in its operating range.

A buzzer and light that activate when air pressure drops below about 60 psi, warning the driver that braking power is failing and the vehicle must be stopped safely.

A heavy spring that applies the brakes automatically when air pressure is released, functioning as the parking brake and as an emergency brake if air pressure is lost.

An emergency braking technique for vehicles without antilock brakes in which the driver applies the brake fully, releases when wheels lock, and reapplies, repeating until stopped.

Braking as hard as possible just short of the point where wheels lock, keeping steering control while producing maximum stopping force.

An electronic system that rapidly releases and reapplies brake pressure to prevent wheel lockup, helping the driver keep steering control during hard braking on slippery surfaces.

Loss of tire traction in which wheels slide instead of roll, usually caused by braking too hard, accelerating too fast, or turning too sharply for the road conditions.

Recovery from a drive-axle skid by releasing the brakes, easing off the accelerator, and steering in the direction the rear of the vehicle is sliding until traction returns.

Recovery from a steering-axle skid, often called a plow skid, by releasing the brakes and letting the front wheels roll again so steering control returns before turning.

The safety margin of clear space kept around a commercial vehicle so the driver has room to stop or maneuver if traffic ahead or beside suddenly changes.

The guideline of staying at least one second per ten feet of vehicle length behind the vehicle ahead, plus one extra second for speeds above 40 mph.

How far down the road a driver scans for hazards, generally about 12 to 15 seconds of travel time at highway speed, so problems are seen early enough to react.

Areas beside and behind a large vehicle where other drivers cannot be seen in the mirrors; truck drivers must check mirrors and turn their heads to cover them.

Setting flat and convex mirrors so the driver can see the sides and rear of the vehicle and trailer, including the trailer wheels and the lane beside the cab.

Using turn signals and brake lights to tell other drivers what you intend to do, given early enough and long enough for them to react safely.

The skill of continuously scanning the roadway, mirrors, and surroundings to identify potential dangers early, before they require an emergency response.

A pre-planned path of travel, such as an open shoulder or lane, that a driver can use if a hazard ahead requires an emergency maneuver.

A sudden action such as hard braking, swerving, or leaving the roadway taken to avoid a crash, requiring quick decisions and firm control of the vehicle.

The procedure for returning to the pavement after dropping a wheel off the edge: hold the wheel firmly, slow gradually, and steer back on only when the tire can climb the edge gently.

The outward push felt in a turn that increases with speed and steering sharpness; it can cause a rollover if speed is too high for the curve.

A crash in which the vehicle tips onto its side or roof, most often caused by taking a curve too fast, steering too sharply, or having a high center of gravity.

Choosing a safe speed based on weather, traffic, road surface, visibility, and vehicle load rather than simply obeying the posted limit.

A shifting method for non-synchronized manual transmissions: clutch in, shift to neutral, clutch out, clutch in again, then shift into the next gear while matching engine speed.

Shifting a non-synchronized transmission without using the clutch by matching engine and road speed; it requires skill and can damage the transmission if done poorly.

Adjusting engine speed so it matches the speed needed for the next gear, allowing a smooth shift and preventing gear clash or engine lugging.

Operating an engine at too low an RPM under load, which strains the engine and drivetrain; the driver should downshift before the engine begins to labor.

Tying down, blocking, or bracing a load so it cannot shift, fall, or spill, using tiedowns and devices rated for the weight of the cargo.

The combined strength rating of all tiedown assemblies holding a load; it must be at least half the weight of the cargo being secured.

Placing cargo so weight is spread properly over the axles, respecting axle and gross weight limits and keeping the center of gravity low.

Legal maximums for a commercial vehicle, commonly 13 feet 6 inches in height and 80,000 pounds gross weight, with axle and bridge-formula limits also applying.

The pivoting hitch plate on a tractor that locks onto the trailer kingpin; a driver must confirm the jaws are closed and a pull test shows a secure connection.

The vertical pin under a trailer's front that locks into the tractor's fifth wheel, transferring trailer weight and allowing the combination to pivot in turns.

A legal prohibition on driving a vehicle or operating a motor carrier after serious safety violations, such as critical defects or hours-of-service breaches, are found.

Federal rules capping driving and on-duty time and requiring rest breaks and off-duty periods, designed to prevent fatigue-related crashes.