What is the minimum Gross Combination Weight Rating (GCWR) for a combination vehicle that requires a CDL?

26,001 pounds or more, provided the GVWR of the towed vehicle is over 10,000 pounds.

What is the passenger capacity that requires a CDL for a vehicle?

16 or more passengers (including the driver).

What type of cargo, regardless of vehicle size, requires a CDL?

Any size vehicle which requires hazardous material placards or is carrying material listed as a select agent or toxin.

What does a Class A CDL authorize the licensee to operate?

Tractor/Trailer or Combination of vehicles with a GCWR of 26,001 or more pounds if the GVWR of the towed vehicle is in excess of 10,000 pounds.

What does a Class B CDL authorize the licensee to operate?

Any single vehicle with a GVWR of 26,001 or more pounds; Any such vehicle towing a vehicle not in excess of 10,000 pounds GVWR.

What does a Class C CDL authorize the licensee to operate?

Any single vehicle less than 26,001 pounds GVWR designed to transport 16 or more passengers or used in hazardous materials transportation.

What is a CDL endorsement?

An additional certification on your CDL that allows you to drive certain types of vehicles or haul specific types of cargo.

What does the H - Hazardous Materials (HazMat) endorsement allow a driver to do?

Haul hazardous materials like fuel, chemicals, or explosives.

What are the requirements for obtaining an H - Hazardous Materials (HazMat) endorsement?

TSA background check and a HazMat knowledge test.

What does the N - Tank Vehicles endorsement allow a driver to do?

Drive tankers carrying liquid or gaseous materials.

What does the T - Double/Triple Trailers endorsement allow a driver to do?

Pull double or triple trailer combinations.

What does the P - Passenger endorsement allow a driver to do?

Drive passenger vehicles like buses or shuttle vans.

What are the requirements for obtaining a P - Passenger endorsement?

A written and skills test, and a background check (which varies by state).

What are the requirements for obtaining an S - School Bus endorsement?

A P endorsement and an additional skills test, plus background and driving record checks.

What does the X - Combination of Tanker and HazMat endorsement allow a driver to do?

Transport hazardous liquids or gases in tank vehicles.

What are the requirements for obtaining an X - Combination of Tanker and HazMat endorsement?

Both HazMat and Tanker tests, and a TSA background check.

What is a general step to obtain a CDL endorsement?

Study the appropriate sections of the CDL manual.

What is the primary purpose of the TSA background check for HazMat or X endorsements?

To ensure national security by vetting individuals transporting high-risk materials.

What is the general rule regarding CDL holders and driving standards?

CDL holders are held to a higher standard when operating any type of motor vehicle on public roads.

Is it legal for a driver to have a CDL from more than one state?

No, it is illegal to have a license from more than one state.

What is required for a person to be physically qualified to drive a commercial motor vehicle?

A Medical Examiner's Certificate through a Medical Examiner within the National Registry of Certified Medical Examiners.

What is the purpose of "Self-Certification" for CDL holders?

To declare their type of commercial operation (e.g., Interstate non-excepted) in accordance with federal regulations.

Can a person drive a commercial motor vehicle if they are disqualified for any reason?

No, a person may not drive a commercial motor vehicle if disqualified for any reason.

What is a consequence for leaving the scene of an accident in a CMV?

Disqualification from driving a commercial motor vehicle.

What is the general rule for who must be tested under FMCSA drug and alcohol testing requirements?

Each driver who operates a commercial vehicle in interstate or intrastate commerce that is required to have a CDL.

What five types of drugs are specifically tested for under DOT regulations?

Marijuana, cocaine, opiates, amphetamines, and phencyclidine (PCP).

What is the requirement for a driver applicant regarding pre-employment drug testing?

They cannot be used until a verified negative drug test result is obtained.

Under what condition is pre-employment drug testing NOT required for an applicant?

If they participated in a drug testing program within the previous 30 days and were tested for drugs within the past 6 months or participated in a random drug testing program for the previous 12 months.

When is a DOT-mandated post-accident drug and alcohol test required for a CMV driver?

If the accident results in a death or a citation for a moving violation.

For a post-accident test involving bodily injury requiring immediate medical treatment away from the scene, when is a test required for the CMV driver?

Only if a citation is issued to the CMV driver.

When can random alcohol testing be conducted on a driver?

Only when a driver is on duty, just before driving, or just after driving.

What must a determination of reasonable suspicion for drug or alcohol testing be based on?

Specific, contemporaneous, and articulable observations of the driver's appearance, behavior, speech, or body odors.

What is the minimum training requirement for a company official making a reasonable suspicion determination?

60 minutes on drug use and an additional 60 minutes on alcohol misuse.

What is the requirement for laboratories used for urine specimen testing under DOT regulations?

They must be certified by the U.S. Department of Health and Human Services.

What is the primary role of a Medical Review Officer (MRO)?

To review, interpret, and report test results, contacting the driver for legitimate explanations before verifying positive results.

What is the purpose of "split samples" in urine drug testing?

To provide a portion of the specimen for retesting at a different certified lab if the primary sample is confirmed positive.

What is the consequence for a driver who refuses a required DOT drug or alcohol test?

A one-year disqualification from operating a commercial vehicle if it's a post-accident test after a fatal accident.

Iowa DOT Cheat sheet (2026)

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