How Many Questions Are on the Colorado CDL Test — 2026

The Colorado CDL knowledge exam is not one test — it is a series of separate tests depending on which CDL class and endorsements you are seeking. Each test has a different number of questions, a different passing threshold, and covers different content from the official Colorado CDL Driver Manual (Form DR 2251). This guide gives you the exact question count, passing score, and topic breakdown for every Colorado CDL knowledge test in 2026.

In This Guide

• Quick Reference — All Tests at a Glance
• Required Tests — General Knowledge, Air Brakes, Combination
• Endorsement Tests — Hazmat, Tanker, Doubles, Passenger, School Bus
• Test Format and Rules
• Retake Rules and Waiting Periods
• What to Study for Each Test
• Frequently Asked Questions

Quick Reference — All Colorado CDL Tests at a Glance

Blue left border = required test. Amber left border = optional endorsement test.

For a Colorado Class A CDL with air brakes: You must pass General Knowledge (50 questions), Air Brakes (25 questions), and Combination Vehicles (20 questions) — a total of 95 knowledge test questions across three separate tests, all at the same DMV appointment.

Required Knowledge Tests

General Knowledge Test — What It Covers

The General Knowledge test is the foundation of the Colorado CDL knowledge exam. Every CDL applicant takes this test regardless of license class or endorsements sought. It is based on Sections 1 through 4 of the Colorado CDL Driver Manual (DR 2251).

• Vehicle inspection procedures — pre-trip and en-route
• Basic vehicle controls — steering, backing, turning
• Shifting gears — manual and automatic transmissions
• Backing safely — mirrors, spotters, reference points
• Visual search — scanning, mirrors, blind spots
• Communication — signals, horns, lights, positioning
• Speed management — stopping distance, curves, grades
• Space management — following distance, lane positioning
• Hazard perception — identifying and responding to hazards
• Emergency maneuvers — evasive steering, off-road recovery
• Skid control and recovery
• Accident procedures
• Cargo — securing, weight limits, load balance
• Mountain driving — grades, runaway ramps, chain laws

Air Brakes Test — What It Covers

The Air Brakes test is required if the vehicle you are seeking a CDL for has air brakes. If you skip this test or fail it, your CDL will have an air brake restriction — meaning you cannot legally drive any vehicle equipped with air brakes. Most Class A commercial trucks use air brakes, so skipping this test severely limits your career options. It is based on Section 5 of the Colorado CDL Driver Manual.

• Air brake system components — compressor, tanks, valves, chambers
• Dual air brake systems
• Inspecting air brakes — 7-step inspection procedure
• Using air brakes — normal stops, emergency stops
• Air brake application pressure — normal operating range (100–125 PSI)
• Low air pressure warning — activates at 60 PSI
• Spring brakes — apply below 20–45 PSI
• Emergency situations and brake failure

FastLessonHub tip: The Air Brakes test has the most specific number memorization of any CDL test. Know these numbers cold: normal air pressure (100–125 PSI), low pressure warning (60 PSI), spring brake application (20–45 PSI), and the 3-step LAB check sequence. Our free Air Brakes practice test covers all 140 questions mapped to Section 5 of the DR 2251.

Combination Vehicles Test — What It Covers

The Combination Vehicles test is required for Class A CDL applicants — anyone seeking to drive tractor-trailers, tanker combinations, or other combination vehicles. It is based on Section 6 of the Colorado CDL Driver Manual.

• Coupling and uncoupling procedures — 5-step coupling checklist
• Inspecting combination vehicles
• Driving combination vehicles safely
• Preventing rollovers — trailer roll tendency, speed in curves
• Preventing jackknifes — braking technique, trailer swing
• Rear trailer sway and off-tracking
• Converter dollies and multi-trailer combinations

Endorsement Knowledge Tests

Endorsements allow you to operate specialized vehicles or haul specific types of freight. Each endorsement requires passing an additional knowledge test at the Colorado DMV. Some endorsements also require ELDT theory training before you can take the knowledge test.

Hazmat test language restriction: The Colorado CDL Hazmat knowledge test is available in English only. All other CDL knowledge tests in Colorado are available in both English and Spanish. If English is not your primary language, be aware of this limitation before scheduling your Hazmat test.

Test Format and Rules

Computer-Based Testing

All Colorado CDL knowledge tests are administered on a computer at the DMV. Questions are multiple choice with four answer choices (A, B, C, D). You can navigate between questions and change answers before submitting. The computer displays your score immediately after you finish.

Taking Multiple Tests in One Appointment

If you are applying for a Class A CDL with air brakes, you can take all three required tests — General Knowledge, Air Brakes, and Combination Vehicles — in a single DMV appointment. Plan for 2 to 3 hours for your appointment when taking multiple tests. Tests are taken one at a time on the computer.

The 80% Passing Rule — No Exceptions

Every Colorado CDL knowledge test requires a minimum 80% score. There is no rounding up. If the passing threshold is 40 out of 50, you need exactly 40 — 39 is a failing score. Aim for 85%+ in practice before your appointment to give yourself a comfortable buffer for test-day nerves.

Test Results Are Valid for One CLP Issuance Only

Your knowledge test results are only valid for one issuance of a Commercial Learner's Permit. Once your CLP is issued, if you decide to change your CLP class or add endorsements, you must retake all required exams. Choose the class and endorsements you want before taking your knowledge tests.

Important: The Colorado DMV strongly recommends taking all required knowledge tests at the same appointment. Taking them on separate days means multiple DMV appointment wait times and may create complications if you want to change your CLP class or endorsements later.

Retake Rules and Waiting Periods

How Many Times Can You Retake the Colorado CDL Knowledge Test?

There is no limit on the number of retake attempts for Colorado CDL knowledge tests. You can retake each test as many times as needed until you pass.

Waiting Period Between Attempts

Colorado requires a minimum 1-day waiting period between CDL knowledge test attempts. You cannot retake a failed test the same day. Each retake requires a new DMV appointment.

What Happens If You Fail One Test But Pass Others

If you fail one test during your appointment but pass others, you only need to retake the test you failed. You do not need to retake the tests you already passed. Your passing test results are saved in the system.

Skills Test Retakes

The CDL skills test (pre-trip, backing, road test) is different from the knowledge tests and is taken at a third-party testing facility. If you fail any component of the skills test, you must retake only the failed component — not the entire test. Each retake costs approximately $275. There is no limit on skills test retakes, and Colorado does not impose a waiting period between skills test attempts beyond scheduling availability.

What to Study for Each Test

All Colorado CDL knowledge test questions come directly from the official Colorado CDL Driver Manual (Form DR 2251), published by the Colorado Division of Motor Vehicles. You can download it free at dmv.colorado.gov .

Most Commonly Tested Topics — General Knowledge

• Stopping distances at various speeds and road conditions
• Pre-trip inspection — 7-step inspection procedure and what to check
• Following distance — 1 second per 10 feet of vehicle length at speeds under 40 mph
• Speed limits in school zones, construction zones, and bad weather
• Cargo securement rules — tie-downs, blocking, bracing
• Weight limits — federal bridge formula, axle weight limits
• Colorado mountain driving — gear selection, runaway ramps, chain laws

Most Commonly Tested Topics — Air Brakes

• Air brake system components and function
• Normal air pressure range: 100–125 PSI
• Low pressure warning: activates at 60 PSI
• Spring brake application: below 20–45 PSI
• 3-step LAB (Leaks, Application, Build-up) inspection
• Dual air brake system operation
• Brake fade and heat buildup on long downgrades

Most Commonly Tested Topics — Combination Vehicles

• 5-step coupling procedure — in correct order
• Uncoupling procedure
• Preventing trailer rollover — speed in curves, high center of gravity
• Preventing jackknife — when it occurs and how to avoid it
• Off-tracking on turns — how trailers cut corners
• Converter dollies — when required and how to inspect

Use our free practice tests. Our Colorado CDL practice tests are mapped directly to the DR 2251 manual and include all three required knowledge areas — General Knowledge , Air Brakes , and Combination Vehicles . Each question includes a rationale explaining why the correct answer is right. No signup required.

Frequently Asked Questions

How many questions are on the Colorado CDL test?

The answer depends on which tests you are taking. For a Class A CDL with air brakes — the most common path — you take three tests totaling 95 questions: General Knowledge (50 questions), Air Brakes (25 questions), and Combination Vehicles (20 questions). Each test must be passed separately with a score of 80% or higher.

What is the passing score for the Colorado CDL test?

The passing score for all Colorado CDL knowledge tests is 80%. You must correctly answer at least 80% of the questions on each individual test. There is no combining scores across tests — each test must independently reach 80%.

How long does the Colorado CDL knowledge test take?

Each test takes approximately 20 to 45 minutes depending on how quickly you work through the questions. If you are taking all three tests for a Class A CDL with air brakes, plan for 1 to 2 hours of testing time plus DMV check-in and processing time. Your total DMV appointment may run 2 to 3 hours.

Can I take the Colorado CDL test in Spanish?

Yes. Confirm permitted CDL testing languages directly with the Colorado DMV; federal English-language proficiency requirements for commercial driving are separate from test administration. When booking your DMV appointment, notify the office if you need the Spanish version.

What happens if I fail part of the CDL test?

If you fail one test but pass others at your DMV appointment, you only need to retake the failed test. You do not lose credit for tests you passed. There is no limit on retakes and Colorado requires a 1-day minimum waiting period between attempts. Each retake requires a new DMV appointment.

Do I need to take the Air Brakes test for a Class A CDL?

Technically no — but practically yes. The Air Brakes test is not legally required to receive a Class A CDL. However if you do not take it and pass, your CDL will have an air brake restriction that prohibits you from operating any vehicle with air brakes. Since virtually all tractor-trailers use air brakes, an air brake restriction makes your Class A CDL nearly useless for commercial trucking. Take the Air Brakes test.

Practice Every Colorado CDL Test Question — Free

Our free practice tests cover General Knowledge, Air Brakes, and Combination Vehicles — the available questions mapped to the official Colorado CDL Manual. No signup required.

Use practice scores as diagnostics

Study Colorado’s current commercial driver manual and match practice sessions to the required knowledge areas for your class and endorsements. Practice questions are not official live-exam questions. Verify current test language availability, retake policies and required test modules with the licensing agency rather than relying on historical question counts.

Helping Colorado commercial drivers pass their permit exams with confidence.