Idaho DMV Practice Test 2025

The Idaho Transportation Department (ITD) administers a 40-question multiple-choice knowledge test — one of the longest in the nation. You must correctly answer at least 34 questions (85%) to pass. The test covers traffic laws, road signs, safe driving practices, and Idaho-specific topics including the open range law, mountain driving, and seasonal hazards. The test is based on the Idaho Driver's Manual. If you fail, a waiting period applies before retaking.

Idaho Code § 25-2118 establishes open range territory in much of rural Idaho. In open range areas, livestock have a legal right to be on the road, and if a driver hits cattle, the driver is legally responsible for any damages to the animals — not the rancher. Ranchers are not required to fence livestock out of public roads in open range territory. Drivers must prove that the livestock were not lawfully in the right-of-way to avoid liability. This is the opposite of how liability works in fenced-range states and is critical knowledge for Idaho drivers on rural roads.

Idaho's GDL has three stages. At age 14½, teens may obtain an instruction permit after passing the knowledge test. The permit holder must be accompanied by a licensed driver 21 or older at all times. At age 15, after at least 6 months with the permit and completing required supervised driving hours, a Supervised Instruction Permit (restricted license) is available after passing a road skills test. At age 17, after meeting all GDL requirements with a clean record, a full unrestricted license is available.

Idaho Code § 49-1401A prohibits ALL drivers from reading, typing, or watching on a handheld wireless device while driving — primary enforcement, meaning an officer can stop a driver solely for this violation. Adults may make a one-touch call using a handheld device, but drivers under 18 face a complete ban on all handheld device use while driving. Hands-free use — a phone in a dashboard or windshield mount, Bluetooth calling, or earpiece — is permitted for all drivers. Fines are $75 (first offense), $150 (second), and $300 (third or subsequent).

Idaho has significant mountain driving hazards on several routes. ID-75 (Sawtooth Scenic Byway) crosses Galena Summit at over 8,700 feet with steep grades and snowfall possible any month of year at elevation. US-95 through the Salmon River Canyon has documented rockfall, sections with no guardrail, and single-lane passing zones. US-12 over Lolo Pass along the Clearwater River can have avalanche and ice hazards in winter. Drivers should carry emergency supplies, check weather and road conditions before mountain travel, and be prepared for rapid weather changes at elevation.

Idaho DUI law sets a BAC limit of 0.08% for adult drivers 21 and older and a limit of 0.02% for drivers under 21. Commercial drivers operating a CMV face a 0.04% limit. DUI penalties in Idaho include mandatory license suspension (90 days minimum for a first offense), fines, possible jail time, and potential ignition interlock device requirements. Idaho uses 'DUI' (Driving Under the Influence) terminology.

Southern Idaho's agricultural industry — primarily potatoes, grain, and dairy — creates specific road hazards from August through October during harvest season. Heavy, wide, and slow-moving farm equipment (potato harvesters, combines, grain wagons) travels on rural roads at 25 mph or less. Drivers must slow down, maintain safe following distance, and pass only when safe. On dry days in the Snake River Plain, potato and grain harvest also creates dust plumes that can reduce visibility on adjacent roads. Dust devils are common on hot, sunny days.

Idaho's instruction permit is available at age 14½. The permit holder must be accompanied at all times by a licensed driver who is at least 21 years old and seated in the front seat. Idaho law requires the supervising driver to hold a valid Idaho driver's license. Permit holders may not drive after midnight or carry passengers outside the immediate family without the supervising driver present. After meeting all GDL requirements, a provisional license is available at age 15.

Dust devils are small but intense whirlwinds that form when ground-level hot air rises rapidly, creating a rotating column of dust, dry soil, and debris. They are common on the Snake River Plain in southern Idaho on hot, sunny days. Dust devils can appear suddenly on or near roads and momentarily reduce visibility to near zero. They can also carry rocks and debris that can chip windshields. Drivers should slow down and turn on headlights when a dust devil is near their path, but should not swerve suddenly into other lanes to avoid them.

Idaho does not require periodic vehicle safety inspections for most passenger vehicles. Vehicles must meet safety equipment standards (lights, brakes, etc.) to operate legally on Idaho roads, but Idaho does not have a mandatory annual or biennial inspection program. Some commercial vehicles are subject to FMCSA inspection requirements. New residents registering vehicles in Idaho from states with inspection requirements should still ensure their vehicles are in safe operating condition, as defective equipment violations can result in traffic citations.