Idaho Permit Test Cheat Sheet
A condensed, skimmable recap of the rules most worth knowing cold before your exam — distilled from our full Idaho practice question bank. This isn't a replacement for the Idaho Driver's Manual; confirm anything time-sensitive with Idaho DMV.
Idaho Licensing Basics
- The Division of Motor Vehicles (DMV), part of the Idaho Transportation Department, handles licensing statewide, and unlike several neighboring states that avoid the term entirely, Idaho's agency really does use "DMV" as its genuine official name.
- The knowledge exam is delivered through a computer-adaptive format: up to 40 questions total, but the test actually stops early the moment an applicant reaches 34 correct answers, which works out to an 85% passing threshold — among the highest required anywhere in the country.
- A Supervised Instruction Permit, commonly shortened to SIP, becomes available starting at 14 and a half years old, though an applicant younger than 18 must first show proof of enrollment in, attendance at, or graduation from a recognized high school or an equivalent program before that permit can actually be issued.
Graduated Steps & Restrictions
- An approved driver's ed program for an under-18 applicant runs 30 hours of classroom instruction, plus 6 hours of in-car observation and 6 more hours actually behind the wheel with an instructor present throughout.
- The SIP itself has to be held for at least 6 months past finishing that driver's ed program, or until the applicant's 17th birthday arrives, whichever milestone lands first chronologically — and 50 total hours of logged supervised driving are required along the way, 10 of which must happen after dark.
- An underage license becomes available at 15, and for its first 6 months a holder can't carry more than one passenger under 17 who isn't immediate family, a restriction that keeps applying all the way until the driver actually turns 17 themselves.
- Below 16, unsupervised driving is limited strictly to daylight hours, and a fully regular, unrestricted license doesn't arrive until 18.
DUI, Alcohol & Drugs
- Zero tolerance for a driver under 21 means a BAC from 0.02% up to just below 0.08%, well under the standard 0.08% adult limit.
- Commercial drivers are held to 0.04% BAC, half the standard adult threshold.
- Alcohol degrades judgment, reaction time, coordination, and vision — all necessary for safe driving, even below the legal limit.
Distracted Driving
- Avoid any handheld device use while driving; treat every trip as one where full attention stays on the road.
- Texting while driving is a primary offense for every Idaho driver.
Right-of-Way
- With no signs or signals controlling an intersection, yield to whoever approaches from your right.
- A driver turning left has to let oncoming traffic and crossing pedestrians clear before completing the turn.
- A vehicle already on the roadway has the right-of-way over one entering from a driveway, alley, or parking lot.
Traffic Signals
- A solid red light means a full stop; treat a flashing red exactly like a stop sign.
- A flashing yellow signal means proceed with caution — no full stop is required.
- If a signal is dark or malfunctioning, treat the intersection as if every approach had its own stop sign.
Traffic Signs
- Shape is a nationwide code: octagon means stop, downward-pointing triangle means yield, diamond means warning.
- Color carries meaning too — red for stop/yield/prohibition, orange for construction, yellow for warnings.
- A red circle with a diagonal slash is the standard national way to say an action isn't allowed.
Lane Markings & Usage
- Yellow lines separate opposing directions of traffic; white lines separate lanes traveling the same direction.
- A broken line permits a lane change when safe; a solid line discourages crossing.
Turning
- Signal well ahead of the turn itself, so other drivers actually have time to react.
- A right turn on red is generally legal after a complete stop and yielding, unless a posted sign says otherwise.
- A safe U-turn always needs a clear view of traffic in both directions.
Passing
- A double solid yellow line prohibits passing for traffic in either direction.
- The posted speed limit still applies mid-pass.
Following Distance
- Hold at least a 3-second gap in normal conditions, and stretch that further in rain, fog, or heavy traffic.
- Tailgating is a leading cause of rear-end crashes.
Freeway Driving
- Use the acceleration lane to match highway speed before merging.
- Signal and move into the exit lane well ahead of your exit.
Roundabouts
- Traffic circulates counterclockwise, and vehicles already inside have the right-of-way over ones entering.
Railroad Crossings
- Slow down, look both ways, and listen before crossing, even where there are no gates or lights.
- Never stop on the tracks, and never drive around a lowered gate.
Pedestrians & Crosswalks
- Every intersection is a legal crosswalk, marked or not, and pedestrians there have the right-of-way.
- A white cane or guide dog marks a visually impaired pedestrian — stop and yield without exception.
School Zones
- Children move less predictably than adult pedestrians, so slow down and follow any crossing guard's directions.
Bicycles
- Cyclists are generally treated as vehicle operators, with the same rights and duty to follow traffic law.
- Give a cyclist at least 3 feet of clearance when passing.
Sharing the Road with Large Vehicles
- If you can't see a truck driver's mirrors, assume they can't see you either.
- Trucks need much more distance to stop than a car does.
Move Over & Emergency Vehicles
- Move over a lane away from a stopped emergency vehicle when safe, or slow down noticeably if you can't change lanes.
Night Driving
- Switch to low beams within roughly 500 feet of an oncoming vehicle so you don't blind the other driver.
Fatigue & Drowsy Driving
- Yawning, heavy eyelids, and drifting out of your lane are early signs your body is losing the fight to stay alert.
Vehicle Equipment
- Headlights are generally required starting a half hour after sunset through a half hour before sunrise.
Work Zones
- Fines commonly double for violations inside a posted, active construction or maintenance zone.
Insurance & Registration
- Drivers must be ready to present a license, registration, and proof of insurance at any traffic stop.
After a Collision
- Check for injuries and call 911 before dealing with any paperwork.
- Stop and exchange information with everyone involved — leaving without doing so is a hit-and-run.
Seatbelts & Child Safety
- Idaho law requires a seatbelt for the driver and every passenger, front seat and back.
School Buses
- Traffic in both directions on an undivided road must stop for a school bus with flashing red lights, and wait until the lights stop flashing.
Speed Limits
- The basic speed law requires a safe speed for conditions, which can be lower than the posted limit.
Signs to Know
Quick visual recap of commonly tested signs — see the full Permit practice test for sign-recognition questions.
Come to a complete stop, then proceed only when it is safe to do so
Slow down and be ready to stop, giving the right-of-way to other traffic or pedestrians
Do not drive past this sign in this direction; the roadway is closed to traffic entering here
You are driving against the flow of traffic and must safely turn around or stop immediately
Traffic on this road or lane may only travel in the direction the arrow points
Making a U-turn is prohibited at this location
The maximum legal speed under normal conditions on this road is 55 mph
A railroad track crosses the road ahead; slow down, look, and listen for a train before crossing
Parking is not allowed in this area
Drivers may not turn right at this intersection while the signal is red
Two lanes of traffic ahead are merging into one; be prepared to adjust speed and position
The road ahead curves; reduce speed as needed for the curve
You are entering a section of road with traffic moving in both directions; stay in your lane
A stop sign is ahead; begin slowing down now to be able to stop when you reach it
Drivers must keep to the right of a divider, island, or obstruction ahead
Passing other vehicles is prohibited in this zone
Watch for pedestrians and slow down or stop if needed
Slow down and watch for children crossing near the school
Watch for cyclists who may be crossing or entering the road ahead
Watch for deer crossing, especially at dawn or dusk
Last reviewed: 2026-07-23