Colorado CDL Study Guide
Colorado issues commercial driver licenses through the Department of Revenue Division of Motor Vehicles. The state follows federal CDL rules in its Commercial Driver License Manual (DR 2251). You can drive a commercial vehicle inside Colorado at 18. You must be 21 to drive across state lines or carry hazardous materials.
Key Colorado numbers
- Minimum age (intrastate): 18
- Minimum age (interstate or hazmat): 21
- CLP hold before skills test: at least 14 days
- General Knowledge passing score: 80%
- General Knowledge test: ~50 questions
- Air Brakes test: ~25 questions (required if your vehicle has air brakes)
- Combination Vehicles test: ~20 questions (required for Class A)
Topics on the Colorado General Knowledge test
- Vehicle inspection (pre-trip, en-route, post-trip)
- Driving safely (speed management, space management, hazard perception)
- Transporting cargo safely
- Air brakes (if your vehicle is air-braked)
- Combination vehicles (Class A)
If you fail a test
If you fail a CDL knowledge or skills test in Colorado, you may schedule a retake at the DMV. Additional fees may apply. See the Colorado DMV First-time CDL Driver page for current retake details.
Frequently asked questions
How old do I need to be to get a CDL in Colorado?
You must be at least 18 to drive a commercial vehicle inside Colorado. You must be 21 to drive across state lines or carry hazardous materials.
How long must I hold my Colorado CLP before the skills test?
You must hold your Commercial Learneru0027s Permit for at least 14 days before you can take the CDL skills test.
How much does a Colorado CDL cost?
The CLP is $19 and the 4-year CDL is $17.50. Endorsements start at $5 each.
Do I need to take Entry-Level Driver Training in Colorado?
Yes. If you are getting your first Class A or B CDL, or your first H, P, or S endorsement, you must complete federal ELDT from an FMCSA-registered provider.
Do I need a DOT medical card to get a Colorado CDL?
Yes. You must complete a DOT medical exam and submit your Medical Examineru0027s Certificate to the Colorado DMV.
What is the official Colorado CDL manual?
The Colorado CDL Manual (DR 2251) is the official study guide. You can download it free from dmv.colorado.gov.
Free practice
Start a Colorado General Knowledge quiz →
Sources: Colorado CDL Manual PDF (DR 2251, June 2023) Colorado DMV CDL General Information Colorado DMV Iu0027m a Commercial Driver Colorado DMV First-time CDL Driver