Iowa Department of Transportation
Iowa CDL practice tests
How Iowa handles the commercial learner permit, the fees and the skills test.
- General Knowledge24 questions, required of every applicant
- Air Brakes20 questions, skip it and an L restriction applies
- Combination Vehicles18 questions, needed for Class A
- Hazardous Materials20 questions, endorsement H
- Tank Vehicles16 questions, endorsement N
Every knowledge area
The 145 questions are the same in every state. Start with general knowledge, then sit the areas Iowa will write onto the permit.
General Knowledge
Required of every applicant: inspection, control, space and speed management, hazard perception, emergencies and hours of service.
Air Brakes
Air brake knowledge and vehicle checks for applicants who may drive vehicles with air brakes.
Combination Vehicles
Coupling, the fifth wheel, off tracking and trailer swing. Needed for Class A.
Hazardous Materials
Placards, shipping papers, segregation and the security threat assessment.
Tank Vehicles
Liquid surge, baffles, outage and why a tanker rolls over so readily.
Doubles and Triples
Rearward amplification, converter dollies and coupling a second or third trailer.
Passenger Transport
Bus inspection, standee lines, passenger supervision and railroad crossings.
School Bus
Danger zones, loading and unloading, student crossing and evacuation.
What is different in Iowa
Iowa in particular
Iowa spreads CDL testing across three separate channels rather than one, DOT service centers, county treasurer offices, and licensed third parties, and it requires those third party examiners to carry a $50,000 surety bond and pass an AAMVA certified examiner course before they can test anyone.
The written exams themselves are federal
Iowa decides the permit rules, the fees and who runs the skills test, but the knowledge you are tested on comes from 49 CFR Part 383 and is the same in every state, which is why the 145 questions here work wherever you apply.
What changes in this state
Commercial learner permit
Iowa requires a commercial learner permit to be held for at least 14 days before the skills and drive test, and the permit is valid for one year from issuance with no renewal.
Iowa Department of Transportation, Commercial Learner Permits, checked Aug 28, 2026Fees
A commercial learner permit costs $12 through the Iowa DOT.
Iowa Department of Transportation, Commercial Learner Permits, checked Aug 28, 2026Where you test
Knowledge and skills tests in Iowa are offered at DOT driver's license service centers, at some county treasurer offices, and through DOT authorized third party testers, all giving the same test.
Iowa Department of Transportation, Third-Party Testers, checked Aug 28, 2026Iowa CDL written exams, in the federal format.
145 cited questions, free, with nothing to sign up for. The permit rules above are Iowa's. The knowledge is 49 CFR Part 383.