CDL General Knowledge Test 3

Correct shifting ensures you have engine braking when needed and prevents stalling or getting stuck in neutral, which compromises your control of the vehicle.

Study focusUse inspection habits to catch unsafe defects before driving.

Common trapChecking only obvious items and missing brake, tire, coupling, or defect-report steps.

If headlights fail, immediately turn on hazard lights or turn signals to make yourself visible, slow down, and steer to a safe stop off the roadway.

Study focusUse inspection habits to catch unsafe defects before driving.

Common trapChecking only obvious items and missing brake, tire, coupling, or defect-report steps.

You should maintain highway speed until you are in the deceleration lane, then brake to slow down to the posted ramp speed before entering the curve.

Study focusChoose safe speed, spacing, and visual search habits for commercial vehicles.

Common trapDriving at passenger-car speeds without accounting for weight, space, weather, or grade.

Driving through deep water can soak the brake linings. Wet brakes can be weak, apply unevenly, or grab, leading to a lack of braking power or a skid.

Study focusRespond safely to hazards, emergencies, traction loss, and unsafe conditions.

Common trapReacting late or using sudden braking/steering when controlled action is safer.

To dry wet brakes, slow down, put the truck in a low gear, and lightly apply the brakes for a short distance. The friction generates heat which dries the linings.

Study focusApply core CDL safe-driving rules to common road and vehicle situations.

Common trapMemorizing rules without applying them to driving scenarios.

Mirrors should be adjusted prior to starting the trip so you can see a small portion of your vehicle's side as a reference point to judge where other objects are.

Study focusChoose safe speed, spacing, and visual search habits for commercial vehicles.

Common trapDriving at passenger-car speeds without accounting for weight, space, weather, or grade.

A pull-up is when you pull forward during a backing maneuver to correct your angle or clear an obstacle. You should use as many pull-ups as necessary to back safely.

Study focusUse safe backing, turning, and basic-control habits.

Common trapBacking without a helper or failing to stop when visibility is uncertain.

Loose tie-downs allow cargo to shift. A sudden shift in weight can destabilize the vehicle, leading to loss of steering control or a rollover.

Study focusControl off-tracking, rollover, rearward amplification, and trailer movement risks.

Common trapTurning or steering too sharply without accounting for trailer movement.

In very hot weather, tires can overheat and catch fire or blow out. You must inspect them every 2 hours or 100 miles to ensure they are not too hot to touch.

Study focusApply safe loading, separation, parking, routing, and emergency-response decisions for hazmat.

Common trapChoosing a convenient action instead of the action that protects people and isolates the hazard.

Heavy steering or pulling to one side is a strong indicator of a front tire blowout or severe under-inflation. You must stop safely and inspect the tires immediately.

Study focusUse pre-trip inspection habits to identify unsafe vehicle-system defects before driving.

Common trapMemorizing a walk-around order without understanding which defects make the vehicle unsafe.

Railroad crossings require early observation and enough space beyond the tracks. A commercial vehicle should not enter unless it can clear the crossing safely.

Source focusCDL Manual - Driving Safely: railroad crossings

Study focusApply safe railroad crossing decisions to commercial vehicle movement.

Common trapEntering a crossing before there is room to clear it.

A missed shift can stall the vehicle or interrupt movement at the worst possible place. Choose the gear before crossing.

Source focusCDL Manual - Driving Safely: railroad crossings

Study focusUnderstand why gear choice should be settled before a railroad crossing.

Common trapTreating a railroad crossing like an ordinary road segment.

Mountain driving requires planning before the descent. Entering too fast can overheat brakes and remove safe control options.

Source focusCDL Manual - Driving Safely: mountain driving

Study focusChoose the safe setup before a downgrade.

Common trapTrying to solve downgrade speed after the vehicle is already too fast.

Escape ramps are emergency features for runaway or uncontrollable vehicles on grades. They are not routine stopping areas.

Source focusCDL Manual - Driving Safely: mountain driving

Study focusRecognize when an escape ramp is the safe emergency option.

Common trapTreating an escape ramp as a normal parking or convenience area.

Fog reduces visibility and can make distance judgment unreliable. Low beams, slower speed, and more space improve control.

Source focusCDL Manual - Driving Safely: seeing hazards and bad weather

Study focusApply safe low-visibility driving habits.

Common trapUsing high beams or following too closely in fog.

Fatigue reduces alertness and reaction time. The safe response is to stop in a safe place and rest.

Source focusCDL Manual - Driving Safely: staying alert

Study focusChoose a safe response to driver fatigue.

Common trapUsing short-term stimulation instead of stopping to rest.

Do not escalate aggressive-driver situations. A commercial driver should protect space and stay focused on safe control.

Source focusCDL Manual - Driving Safely: aggressive drivers

Study focusRespond safely to aggressive drivers.

Common trapEscalating conflict instead of creating space.

Reading a message takes eyes and attention away from driving. CDL safe driving requires full attention to the road and vehicle.

Source focusCDL Manual - Driving Safely: distracted driving

Study focusIdentify unsafe distracted driving behavior.

Common trapThinking a short distraction is harmless in a large vehicle.

Mirrors are a key visibility tool for a commercial driver. They support lane changes, turns, backing, and awareness around the vehicle.

Source focusCDL Manual - Vehicle Inspection and Seeing

Study focusConnect mirror condition and adjustment to safe driving.

Common trapTreating mirrors as comfort equipment instead of safety equipment.

Signaling communicates your plan, but it does not make the move safe by itself. Check mirrors and space before moving.

Source focusCDL Manual - Driving Safely: communicating

Study focusUse traffic checks and signaling correctly before a lane change.

Common trapUsing a signal as a substitute for checking traffic.