Colorado CDL General Knowledge Practice Test

The Colorado CDL test has 50 questions. You must answer at least 40 correctly — 80% — to pass. The Division of Motor Vehicles (DMV, part of CDOR) administers CDL testing at DMV offices and approved third-party testing sites throughout Colorado.

Colorado's mountain terrain is the defining CDL challenge: I-70 and other mountain highways have mandatory truck inspection stations, chain control requirements, 'Trucks in Right Lane Only' sections on steep grades, and runaway truck ramps for brake failures. CDL drivers must downshift before steep descents, use engine braking, and use snub braking — never ride the brakes continuously. Colorado also has strict chain control enforcement during winter weather.

Yes. Colorado's DWAI (0.05%–0.079% BAC) and cannabis DUI (5 ng/mL THC) in a personal vehicle are criminal convictions that must be reported to FMCSA and can affect CDL employment. CDL holders in a CMV face the federal 0.04% BAC threshold. Cannabis DUI triggers CDL disqualification under FMCSA regulations. Both DWAI and cannabis DUI are criminal records that employers review.

Colorado DOT posts chain control at mountain passes during winter weather. CDL drivers must have chains installed when required by the posted chain control level. CDL drivers should always carry chains when planning mountain routes in Colorado from approximately October through April. Monitor Colorado road conditions at cotrip.org. Driving through chain control without chains results in fines and possible out-of-service orders.

A Colorado CDL is valid for 4 years. Your DOT medical certificate must remain current. HazMat endorsements require TSA security clearance renewal every 5 years. Colorado CDL holders must self-certify their medical status category annually at the DMV.

A Class A CDL allows you to operate any combination of vehicles with a Gross Vehicle Weight Rating (GVWR) of 26,001 lbs or more, provided the towed unit exceeds 10,000 lbs — this includes tractor-trailers and double/triple trailer rigs. A Class B CDL covers single vehicles with a GVWR of 26,001 lbs or more, or any such vehicle towing a unit not exceeding 10,000 lbs — this includes straight trucks and large buses. A Class C CDL is required for vehicles designed to carry 16 or more passengers (including the driver) or for vehicles transporting hazardous materials that require placarding, when those vehicles do not qualify for Class A or B.

CDL fees vary by state and by the class and endorsements you obtain. Most states charge separate fees for the CDL knowledge test ($10–$30 per attempt), the CDL skills test ($50–$150), and the CDL license itself ($50–$100). Additional fees apply for each endorsement (HazMat, Tanker, Passenger, etc.). The HazMat endorsement also requires a TSA security threat assessment fee of approximately $86. Check your Colorado DMV website for current fee schedules.

Federal regulations (49 CFR 383.133) require that CDL applicants be able to read and speak the English language sufficiently to understand highway traffic signs and signals and to respond to official inquiries. Many states offer CDL knowledge tests in Spanish and other languages for non-commercial knowledge questions, but the actual CDL test must be taken in a language that allows the driver to meet the English proficiency requirement. Check with the Colorado DMV for available language options.

In most states, a CDL is valid for 4–8 years (commonly 4–5 years). To renew your Colorado CDL, you typically need to visit a DMV office, pass a vision test, pay the renewal fee, and update your medical certification (DOT physical). If you hold a HazMat endorsement, your TSA background check must also be current. CDLs cannot generally be renewed online due to federal requirements for in-person verification of medical certification.

If you fail the CDL General Knowledge test in Colorado, you are typically required to wait a specified period (commonly 1–7 days) before retaking it. Most states allow 2–3 attempts before requiring additional waiting periods or study requirements. There is usually a retest fee for each attempt. Focus on the areas you missed — most states provide a score sheet showing which topic areas you need to review.