The Department of Transportation recommends 30 hours of classroom study and six hours of on-road instruction for general drivers. So applying for a commercial driver license (CDL), which requires already having a basic license, is a bit like going to driving graduate school.

CDL testing is rigorous, entailing both written examinations and carefully observed testing in the inspecting and driving of Class A, B, or C vehicles.

While you can take any of the written tests required for a CDL license or endorsement at a full-service driver license office, all driving tests are administered by third-party companies in the state of Colorado. These companies charge varying prices but each is certified to evaluate the driving test according to state standards.

Many of these businesses, along with plenty of others, also provide driver training programs for those possessing a CDL training permit, or comprehensive packages that prepare you for both written and driving tests complete with test-like sample questions.

There are two main components to the CDL testing process: knowledge assessment and practical assessment.

The knowledge portion is essentially a battery of written exams that can include just one, or up to five or more sections depending on the type of endorsements you are trying to achieve. These tests include:

• General Knowledge―All CDL applicants must take and pass this test with a grade of 80% or higher

• Air Brakes

• Combination Vehicles

• Hazardous Material Test ("H" endorsement)― must be taken each year you intend to carry a hazmat endorsement

• Passenger Transport ("P" endorsement)

• School Bus ("S" endorsement)―taken in addition to Passenger Transport if applying to operate a school bus

• Tank Vehicle ("N" endorsement)―needed for operating trucks with 1,000-gallon-plus tanks

• Doubles/Triples ("T" endorsement)

The driving or practical test takes all the elements learned in the knowledge portion of the program and puts it into a real-life setting. Your aptitude is judged in three areas:

• Pre-vehicle inspection―Here you are tested on various points regarding whether the vehicle you are getting ready to operate is ready for driving.

• Basic vehicle control―In a controlled setting simulating the street environment you will be tested on the basics of maneuvering the rig.

• On-road training―No simulation here, but the real thing, and quite possibly the most important part of the test. You take the rig onto the roads and are evaluated on your overall competence in being able to handle a commercial vehicle.

Find more CDL information on Commercial Drivers, Applying for a New CDL, Renewing Your CDL, Replacing a Lost CDL, and Commercial Driver FAQs on this site.

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