Class A
The combination license.
- One run
- 50 questions
- To pass
- 40 of 50
Idaho issues commercial licenses through the Idaho Transportation Department, which runs both the roads and the licensing side of the state under one roof — a different setup from states that keep driver licensing and highway administration in separate agencies. Idaho is also large and thinly populated outside its handful of cities, so the distance between testing offices can be considerable if you live in the rural south or the panhandle rather than near Boise, Idaho Falls or Coeur d'Alene.
Every figure below names the document it came from, so you can check it rather than take our word for it.
Fees change without notice, so we do not repeat them here. Check Idaho Transportation Department for the current cost.
The knowledge tests are set by federal rule, so the questions are the same wherever you sit them. What changes is the paperwork above.
The combination license.
The heavy straight vehicle license. Group B covers a single vehicle rating 26,001 pounds or more, or one towing a unit of 10,000 pounds or less.
The small vehicle license.
The knowledge test every commercial driver takes, whatever class or endorsement they are after.
Required before you may drive any commercial vehicle with air brakes.
Required for a Class A license. Coupling and uncoupling, off-tracking, trailer brakes and the handling of a vehicle that is jointed in the middle.
The H endorsement. Placarding, shipping papers, loading and segregation rules, and what to do when something leaks.
The N endorsement. Surge, baffles, bulkheads, high center of gravity and the way a part-full tank changes how a vehicle stops and turns.
The T endorsement. Coupling and uncoupling multiple trailers, converter dollies, crack-the-whip and the inspection points a second trailer adds.
The P endorsement. Pre-trip and post-trip checks on a bus, loading and unloading, standee lines, and handling passengers on the road.
The S endorsement, taken alongside the passenger endorsement. Danger zones, mirror adjustment, loading and unloading students, and railroad crossings.
A study drill for the pre-trip inspection.
The content of the exam is federal, and Idaho doesn't add much on top of it: 49 CFR Part 383 governs the knowledge tests, the endorsements and the pass mark of 80 percent everywhere, Idaho included. Where Idaho differs is coverage rather than content — because ITD combines transportation planning with licensing, and because the state's population is spread thin, the number of offices actually running CDL knowledge tests is smaller relative to the state's size than in a more densely populated state. Planning the drive is often the real first step, not the studying.
Everyone starts with general knowledge. After that it depends on the vehicle you'll drive. Air brakes require their own exam, and failing it doesn't block a license — it restricts it, barring air-braked vehicles until you pass. A trailer over 10,000 pounds pulls in the combination vehicles exam too. Beyond that, the endorsements: tank, doubles and triples, passenger, school bus, hazardous materials.
Hazmat needs a Transportation Security Administration background check as well as the written exam, and that runs on its own federal schedule. In a state where the nearest testing office might already mean a longer trip, it's worth starting the background check well before you plan to sit the written test, so the two aren't both holding you up at once.
A commercial learner permit has to be issued before the skills test, and federal rule sets a minimum number of days it must be held first. Use that window to sit the knowledge exams early rather than late — if a retake is needed and the nearest office is a long drive, you want time on your side, not against you.
We don't publish fees. Idaho sets and changes its own, and printing a number here that's gone stale would send you to an ITD office with the wrong figure in hand. What this site covers instead is what the exams actually ask, with each answer cited to its source. In a state this size, knowing the content cold before you set off is worth more than it would be somewhere with an office on every corner, so treat the drive itself as part of the planning rather than an afterthought once you've studied.
Every question on every one of these is free, and each answer names the handbook page it came from.
Every question names the handbook, section and page it was read from, so you can check the answer instead of taking our word for it.
How we write these