Nebraska CDL General Knowledge key terms

A systematic check of a commercial vehicle's critical parts, including brakes, tires, lights, coupling devices, and emergency equipment, performed before driving to confirm the vehicle is safe and legally roadworthy.

The physical circuit around the vehicle during a pre-trip inspection, used to look at tires, lights, leaks, and securement that cannot be judged from the driver's seat.

Inspecting the ground and under-hood components for dripping oil, coolant, fuel, or air after the engine has run, since fluid loss can signal a defect that makes the vehicle unsafe to operate.

A check where the driver builds air pressure, shuts off the engine, and watches the gauge to confirm the system holds pressure and does not leak beyond the allowed rate.

An audible and visual alert that must activate before air pressure drops too low for safe braking, warning the driver to stop and diagnose the problem rather than continue driving.

An emergency and parking brake that applies mechanically when air pressure is lost, so a vehicle with a serious air leak will brake automatically instead of rolling freely.

The amount of pushrod travel when the brake is applied; too much travel means the brakes are out of adjustment and stopping distance increases, so it must be checked and corrected.

The linkage between the brake chamber pushrod and the brake shoe; its position and travel reveal whether the foundation brakes are properly adjusted.

The measured groove depth remaining on a tire; worn tread reduces traction and can make the tire illegal, so minimum depths must be verified during inspection.

Checking tires for cuts, bulges, exposed cords, mismatched sizes, and improper inflation, any of which can cause a blowout or loss of control at highway speed.

Checking the fifth wheel, kingpin, safety latches, and air lines that connect a tractor to a trailer, confirming the trailer is locked on and will not separate while moving.

After coupling, pulling gently against the locked trailer with the trailer brakes set to confirm the fifth wheel jaw has closed and the trailer cannot slide off the kingpin.

The horseshoe-shaped hitch plate on a tractor that locks around the trailer kingpin, carrying the trailer load and allowing the combination to pivot during turns.

The total distance traveled from the moment a hazard is seen until the vehicle stops, made up of perception distance, reaction distance, and braking distance.

The distance a vehicle travels while the driver recognizes that a hazard exists; it grows with speed and is unaffected by how hard the driver later brakes.

The distance covered between recognizing a hazard and actually applying the brake, which depends on driver alertness and adds directly to total stopping distance.

The gap kept behind the vehicle ahead, commonly at least one second for every ten feet of vehicle length at speeds under 40 mph, and more in poor conditions.

The buffer of empty space kept around a commercial vehicle so the driver has room to react, brake, or steer around a hazard without a collision.

An area beside or behind the vehicle that cannot be seen in the mirrors; large vehicles have big blind spots, so the driver must check mirrors and signal before changing lanes.

Moving from one lane to another after checking mirrors, signaling, and confirming the new lane is clear, done gradually because heavy vehicles respond slowly and swing wide.

The tendency of the rear wheels of a long vehicle to follow a tighter path than the front wheels, so the driver must swing wider on turns to keep the trailer off curbs and other vehicles.

A hazard where a truck turning right swings left first, and a car may slip into the open space on the right; the driver must check mirrors and turn slowly to avoid crushing it.

Driving in reverse, which is the most dangerous maneuver for a large vehicle; it should be avoided when possible and done slowly with mirrors, hazard lights, and a spotter.

A person outside the vehicle who guides the driver during backing; the driver must agree on hand signals and stop immediately if the spotter is lost from view.

A technique for accelerating a manual transmission by upshifting at higher engine rpm as speed increases, which improves fuel economy and reduces wear.

Shifting by pressing the clutch, moving to neutral, releasing the clutch, then pressing it again to engage the next gear, matching engine and transmission speed in a non-synchronized gearbox.

Shifting without using the clutch by matching engine rpm to road speed, a skill that can reduce clutch wear but requires practice and is not allowed in all situations.

A device such as a Jacobs brake that slows the vehicle by restricting exhaust flow, helping control speed on downgrades, but it must be switched off on slippery surfaces to avoid skids.

Selecting a lower gear before starting down a hill so engine braking holds the vehicle back, avoiding reliance on the service brakes, which can overheat and fade.

The controlled speed a driver chooses before descending a hill, matching the gear selected so the vehicle does not gain speed that brakes cannot safely manage.

Loss of stopping power caused by overheated brakes, common after prolonged or repeated braking, which makes the pedal feel soft and increases stopping distance sharply.

Loss of tire contact with the road when water builds up under the tires, causing steering and braking to fail; the driver should slow down and avoid hard braking.

Regaining control after tires lose traction by releasing the brake or throttle, steering in the direction the vehicle needs to go, and avoiding sudden inputs until grip returns.

The skill of scanning ahead, checking mirrors, and anticipating risky situations such as merging traffic, construction, or stopped vehicles so the driver can act early.

Approaching a crossing by slowing, checking for trains in both directions, and never stopping on the tracks; some vehicles must stop before crossing regardless of signals.

Tying down and containing a load with adequate tiedowns, working load limits, and header boards so it cannot shift, spill, or fall onto the road during transport.

The combined strength rating of all tiedowns used on a load; the total must meet the minimum required for the cargo's weight and type.

Placing cargo so weight is balanced and within axle and gross weight limits, keeping the center of gravity low and avoiding overloaded tires or steering axles.

The maximum total weight a vehicle is designed to carry, including its own weight, cargo, fuel, and passengers; exceeding it is unsafe and often illegal.

Federal limits on driving and on-duty time, including maximum driving hours and required rest periods, designed to prevent fatigue-related crashes.

An onboard system that automatically records driving time and duty status, replacing paper logs for most drivers and helping enforce hours-of-service limits.

The record of a driver's duty status, driving time, and rest periods for each day, which must be accurate and available for inspection.

Legal protection that prohibits retaliation against a driver who reports a safety or regulatory violation, refuses to drive an unsafe vehicle, or cooperates with an investigation.