Delaware CDL General Knowledge cheat sheet
Delaware CDL General Knowledge · Keep the key ideas within reach.
CDL General Knowledge: Vehicle Inspection, Control, and Safe Operating Rules
Pre-trip inspection rule: check the same items the same way every time, covering engine compartment, cab and controls, lights, brakes, tires, wheels, suspension, and coupling devices before driving; report defects and do not drive an unsafe vehicle.
Three-point stance for entering and exiting the cab: face the vehicle, keep three points of contact (two hands and one foot, or two feet and one hand), and never jump from the cab.
Air brake leak-down limits: with a fully charged system and engine off, pressure loss must not exceed 3 psi in one minute for a single vehicle, or 4 psi in one minute for a combination vehicle; a 20 psi drop in one minute with the brakes applied signals a serious leak.
Air brake warning: with the engine running, build pressure to governor cut-out, then fan the brakes; the low-air warning buzzer or light must activate before pressure falls below 60 psi, and the spring brakes must apply between 20 and 45 psi.
Stopping distance formula: total stopping distance = perception distance + reaction distance + brake lag distance + braking distance; at 55 mph a loaded rig can need roughly the length of a football field or more on dry pavement.
Speed and space rules: posted limits apply to ideal conditions only; reduce speed on curves, in rain, snow, fog, or on downgrades, and use the four-second following rule for vehicles under 40 feet, adding one second for each 10 feet of vehicle length above 40 feet at speeds over 40 mph.
Downgrade control: select a gear low enough to hold the vehicle without brakes before starting the descent, brake firmly enough to feel the slowdown, then release; never coast in neutral or ride the brakes continuously.
Railroad crossing procedure: slow down, look and listen, shift to a gear that lets you cross without shifting, and do not stop on tracks unless traffic forces it; buses and hazmat vehicles must stop at crossings unless exempted.
Right-of-way and lane rules: signal before every lane change or turn, complete turns into the proper lane, and remember that a large vehicle's right turn may require swinging left first; never pass on the right shoulder or squeeze a truck into a tight turn.