CDL (Commercial Driver License) study guides

Air-brake endorsement covers the components, leak tests, slack adjusters, and emergency procedures for trucks fitted with air-brake systems.

The H endorsement authorises the transport of hazardous materials in placardable amounts and requires a TSA security threat assessment.

The S endorsement covers loading, unloading, evacuation, and danger-zone operations for school-bus drivers transporting students.

The P endorsement is required for any commercial vehicle designed to transport 16 or more passengers including the driver.

The T endorsement authorises pulling more than one trailer — most often two pup trailers behind a truck-tractor.

The N endorsement covers liquid-cargo handling, surge dynamics, baffles, and unloading procedures for tank trucks.

Combination-vehicle theory covers fifth-wheel coupling, kingpin/locking-jaw inspection, off-tracking, and air-line connections.

The pre-trip vehicle inspection is the most-failed CDL skills test segment. Candidates must verbally identify and inspect 100+ items in the correct order.

Basic-controls testing covers off-set alley dock, parallel park, straight-line backing, and right-side parallel — the maneuvering portion of the CDL skills test.

The on-road test puts you in real traffic for 30–60 minutes — the examiner scores lane control, intersection handling, hill starts, and railroad-crossing procedure.

The General Knowledge test (50 multiple-choice questions) is required for every CDL class and covers vehicle systems, road rules, and emergency procedures.

Shifting covers manual transmissions (typically 9- to 18-speed), double-clutching, range and splitter operation, and downshifting on grades.

Cargo securement covers tie-downs, working load limits, blocking and bracing, and DOT inspection criteria for various cargo classes.

Hours-of-service rules limit driving to 11 hours within a 14-hour duty window after 10 hours off; ELDs (Electronic Logging Devices) automate enforcement.

Federal CDL operators must hold a valid DOT medical examiner's certificate (medical card), renewed every 1–2 years.

FMCSA Entry-Level Driver Training (ELDT) is a federal pre-CDL training requirement that all first-time Class A/B applicants must complete at a TPR-registered school.

The L (no-air-brakes) and Z (no-full-air-brakes) restrictions appear on a CDL when the applicant tests in a vehicle without air brakes; removing them requires a separate skills test.

Class A allows combination vehicles (truck + trailer >10,000 lb GVWR); Class B is single-vehicle only. Selecting the right class up-front saves money and matches career intent.

Electronic Logging Devices (ELDs) are required for most interstate CMV drivers; HOS rules cap driving and on-duty time to reduce fatigue-related crashes.

FMCSA Drug & Alcohol Clearinghouse, DOT pre-employment drug screen, and PSP record review are required before a carrier can place a CDL holder behind the wheel.

The Commercial Learner Permit (CLP) authorizes practice driving with a qualified CDL holder before sitting the skills test. Federal law requires holding the CLP for at least 14 days.

FMCSA cargo-securement rules dictate working load limits, tiedown counts, and commodity-specific rules for logs, vehicles, large objects, and dressed lumber.

While 49 CFR Part 383 sets minimum federal CDL standards, individual states add variations: skills-test layouts, intrastate-only restrictions (E/V), and 18 vs. 21 minimum age rules.

CDL holders must self-certify their type of operation (interstate excepted, interstate non-excepted, intrastate excepted, or intrastate non-excepted) and maintain a valid DOT medical card on file.

CSA (Compliance, Safety, Accountability) tracks driver and carrier safety performance. Roadside inspection violations affect both the driver Pre-Employment Screening Program (PSP) record and the carrier Safety Measurement System (SMS) score.