Idaho CDL Practice Test 2025

Idaho CDLs are issued by the Idaho Transportation Department (ITD), Division of Motor Vehicles. Idaho does not have a standalone DMV — all driver licensing is administered through ITD. CDL applicants must visit an ITD driver's license office to take the required knowledge tests, submit a current DOT medical certificate, and schedule a CDL skills test with an ITD examiner or approved third-party tester. ITD offices are located in Boise, Twin Falls, Idaho Falls, Pocatello, Lewiston, Coeur d'Alene, and other communities.

All Idaho CDL applicants must pass the General Knowledge test. Additional tests are required based on the license class and endorsements: Combination Vehicles (Class A), Air Brakes (if the vehicle has air brakes), Passenger Transport, Hazardous Materials (plus TSA security threat assessment), Tank Vehicles, Doubles/Triples, and School Bus. Each test requires a minimum score of 80%. Idaho CDL applicants should also understand Idaho-specific operational requirements including OS/OW permit procedures for agricultural operations.

The FMCSA BAC limit of 0.04% applies to CDL drivers operating a CMV in Idaho. Idaho also prohibits consuming alcohol within 4 hours before operating a CMV. A CDL driver who tests at 0.04% BAC or above is placed out of service and faces CDL disqualification. Idaho's standard DUI limit of 0.08% applies to CDL holders driving personal (non-CMV) vehicles. The under-21 DUI limit of 0.02% applies to CDL holders under 21.

Oversize/overweight (OS/OW) permits from the Idaho Transportation Department are required when a vehicle exceeds standard legal size or weight limits. In Idaho's agricultural sector — particularly during potato and grain harvest from August through October — large farm equipment and loaded grain/potato trucks frequently exceed legal limits on specific routes. CDL drivers must obtain the appropriate OS/OW permit before operating oversize or overweight on Idaho roads, carry the permit in the vehicle, and comply with all route restrictions, travel time limitations, and pilot car requirements specified in the permit.

I-84 in southern Idaho runs from the Oregon border through Twin Falls to Boise and is Idaho's primary freight corridor. CDL considerations on this route include: weigh stations at the Oregon border and in Canyon County near Boise; agricultural oversize and overweight loads common during harvest season; dust visibility hazards during potato and grain harvest operations adjacent to the interstate; crosswind exposure across the Snake River Plain; and winter ice conditions on elevated sections over the Snake River. CDL drivers should monitor Idaho 511 (Idaho road conditions) for I-84 conditions.

A Class A CDL allows you to operate any combination of vehicles with a Gross Vehicle Weight Rating (GVWR) of 26,001 lbs or more, provided the towed unit exceeds 10,000 lbs — this includes tractor-trailers and double/triple trailer rigs. A Class B CDL covers single vehicles with a GVWR of 26,001 lbs or more, or any such vehicle towing a unit not exceeding 10,000 lbs — this includes straight trucks and large buses. A Class C CDL is required for vehicles designed to carry 16 or more passengers (including the driver) or for vehicles transporting hazardous materials that require placarding, when those vehicles do not qualify for Class A or B.

CDL fees vary by state and by the class and endorsements you obtain. Most states charge separate fees for the CDL knowledge test ($10–$30 per attempt), the CDL skills test ($50–$150), and the CDL license itself ($50–$100). Additional fees apply for each endorsement (HazMat, Tanker, Passenger, etc.). The HazMat endorsement also requires a TSA security threat assessment fee of approximately $86. Check your Idaho DMV website for current fee schedules.

Federal regulations (49 CFR 383.133) require that CDL applicants be able to read and speak the English language sufficiently to understand highway traffic signs and signals and to respond to official inquiries. Many states offer CDL knowledge tests in Spanish and other languages for non-commercial knowledge questions, but the actual CDL test must be taken in a language that allows the driver to meet the English proficiency requirement. Check with the Idaho DMV for available language options.

In most states, a CDL is valid for 4–8 years (commonly 4–5 years). To renew your Idaho CDL, you typically need to visit a DMV office, pass a vision test, pay the renewal fee, and update your medical certification (DOT physical). If you hold a HazMat endorsement, your TSA background check must also be current. CDLs cannot generally be renewed online due to federal requirements for in-person verification of medical certification.

If you fail the CDL General Knowledge test in Idaho, you are typically required to wait a specified period (commonly 1–7 days) before retaking it. Most states allow 2–3 attempts before requiring additional waiting periods or study requirements. There is usually a retest fee for each attempt. Focus on the areas you missed — most states provide a score sheet showing which topic areas you need to review.