Delaware CDL General Knowledge: Shared Rules for Every CDL Class
The Delaware CDL General Knowledge test is the required written exam for every CDL applicant, regardless of the class or endorsement added later. It tests the shared foundation: pre-trip inspection, basic control, shifting, seeing hazards, speed and space management, railroad crossings, emergencies, skid recovery, accident procedures, and cargo securement. Delaware DMV draws the test from the federal model CDL manual, so these rules apply to Delaware Class A, B, and C applicants alike.
Vehicle inspection and control
A pre-trip inspection exists to find defects before they become crashes; check tires, wheels, brakes, lights, coupling devices, and cargo securement. Re-check cargo securement within the first 50 miles and every 150 miles or 3 hours, whichever comes first. When backing, get out and look, use a spotter when available, back slowly, and prefer backing toward the driver's side. Do not coast in neutral and do not shift while crossing railroad tracks.
Speed and space
The posted speed limit is a maximum for ideal conditions, not a target. Stopping distance includes perception, reaction, brake lag, and actual braking. Following distance for a CMV is one second for each 10 feet of vehicle length at speeds under 40 mph; add one second when over 40 mph. Worked example: a 60-foot combination vehicle at 55 mph needs 60 ÷ 10 = 6 seconds, plus 1 = 7 seconds. At 55 mph that is about 565 feet, because 55 mph is about 80.7 feet per second and 80.7 × 7 ≈ 565.
Hazard and emergency rules
At railroad crossings, never stop on the tracks. If the vehicle stalls, get everyone out and away, then call the emergency number posted at the crossing. In a rear-wheel skid, steer in the direction of the skid and avoid hard braking. If brakes fail, pump the brakes, use engine braking, apply the parking brake gradually, and look for an escape ramp.
Cargo securement
Cargo must be secured against 0.8 g forward deceleration and 0.5 g rearward and sideways. Use enough tiedowns: one for a short light article, two for articles 5–10 feet or over 1,100 pounds, and two plus one per additional 10 feet for longer articles.
Traps that cost marks
Do not confuse following distance with stopping distance; do not assume a posted limit is safe in rain or fog; do not rely on mirrors alone when backing; do not stop on railroad tracks; do not use one tiedown for a long heavy item; and do not brake hard in a skid.