The knowledge test trips up many first-time applicants. Here's exactly what to study and how to walk in prepared.
The Idaho Class D knowledge test consists of 40 questions. You must score at least 85% to pass — meaning you need at least 34 correct and can miss up to 6 (Idaho Driver's Handbook, p.32).
If you fail, you must wait 3 days before retesting and pay the $5 knowledge-test fee again. The same 3-day rule applies to the skills test, and you must pay both the county and skills-test-examiner fees again (p.32-33).
The knowledge test is administered at county DMV offices through the county sheriff's driver license bureau. There is no official time limit on the test, and it is available in English, Arabic, Chinese, Farsi, French, Korean, Russian, Serbo-Croatian, Spanish, Swahili, Vietnamese, and American Sign Language (p.32).
If you are under 17, you must complete an Idaho-approved Driver Training program (30 classroom + 6 BTW hours) before being licensed, plus the GDL supervised period of 50 hours (10 at night) over a minimum 6-month, violation-free period (p.15-19).
Drivers 21+: 0.08 or more. Under 21: 0.02 or more. Commercial: 0.04 or more. 0.20 or more triggers enhanced penalties. Idaho's implied-consent law means by driving you have consented to a BAC or drug test if suspected of DUI (p.131, 126).
1st DUI conviction: up to 6 months jail, up to $1,000 fine, license suspended 90–180 days with NO driving privileges the first 30 days. Refusing the evidentiary test: $250 civil penalty + 1-year absolute suspension. 2nd refusal in 10 years = 2-year suspension (p.126-132).
DT permit at 14½ (drive only with instructor). After driver training: SIP — drive only with a licensed driver 21+ in the front seat. 50 hours supervised driving (10 at night) over 6 months violation-free. Class D license at 15. Under 16: drive 5 a.m.–10 p.m. only. Under 17 first 6 months: max 1 non-family passenger under 17 (p.15-19).
Idaho's recommended minimum is the 3-second rule under good conditions. In bad weather, multiply that by several. Allow MORE than 3 seconds when following a motorcycle, and 2 car lengths per 10 mph behind a snowplow (p.79, 104, 109).
Residential, business, or urban district: 35 mph. Rural interstate: 75 mph (80 where posted). State highway: 65 mph (70 where posted). Urban interstate: 65 mph. School-zone violations carry increased penalties. Heavy trucks (5+ axles, 26,000+ lb): 10 mph below posted on non-urban interstates, max 65 on urban interstates (p.68-69).
Signal at least 100 feet before turning in business or residential areas. On freeways/highways: signal at least 5 seconds before lane change or exit. Right-on-red allowed after stop and yield (unless posted otherwise). Left-on-red allowed only from a one-way street onto a one-way street, after stop and yield (p.72, 73, 85).
Stop and remain stopped while red lights flash and/or stop arm is extended — until lights are off, arm in, and all children clear of the roadway and bus. Exception: traveling the OPPOSITE direction on a 4+ lane highway (2 lanes each way). Same-direction traffic must always stop. Passing a stopped school bus is always prohibited (p.70, 76).
Required from sunset to sunrise AND any time visibility is 500 feet or less. Dim high beams within 500 feet of an oncoming vehicle and within 200 feet when overtaking. Use low beams in fog and heavy precipitation (p.43, 110).
Within 18 inches of the curb when parallel parking. No parking within 15 ft of a fire hydrant; 20 ft of a crosswalk; 30 ft of a stop/yield sign or signal; 50 ft of railroad tracks; 20 ft of a fire station driveway. Bridges, overpasses, and double-parking always prohibited (p.80-81).
Idaho law requires ALL occupants to wear safety belts/shoulder straps. Children 6 years and younger must be in approved child safety seats. NHTSA recommends children under 13 ride in the back seat. Studded snow tires only October 1 to April 30 (p.40-42).
Idaho needs 85% — at least 34 of 40 correct. Aim for 90%+ during practice so you have a safety margin against tricky wording on test day.
Memorize BAC limits, distances, signal distance, following distances, and suspension periods. These specific numbers appear on virtually every Idaho test.
The Weak Spots mode saves every question you got wrong. Replay it until you're hitting 90%+ before going to the DMV office.
Download the Idaho Driver's Handbook (July 2024) at https://itd.idaho.gov/dmv/. Every question comes directly from this manual.
Idaho's quirks: 75 mph on rural interstates (80 where posted), and a unique 15-mph passing-speed exception that lets you exceed the limit by up to 15 mph while passing on a 2-lane road — only when the posted limit is 55+ and NOT in a work zone (p.68, 76).
Sign questions are visual — shape, color, and meaning all matter. Use the Road Signs Quiz mode to practice all signs before test day.
Free, no signup · Questions verified against the official state driver manual