Idaho Road Signs Cheat Sheet.
The night-before summary, built like the exam.

The numbers to remember

• 40 questions on the knowledge test; you can miss up to 6 and still pass (85%, or 34/40 correct).
• Test fee: $5.00. Fail and you wait 3 days to retest, and pay the $5.00 fee again.
• Instruction permit fee: $20.00; driver training/supervised instruction permit fee: $21.50.
• Driver training/supervised instruction permits available from 14½ years old; full license eligibility starts at 15.
• Test offered in English plus multiple languages (Spanish, Chinese, Arabic, French, Russian, Vietnamese, ASL, and more).

Sign shapes at a glance

• Red octagon = stop, no exceptions.
• Red/white downward triangle = yield.
• Yellow diamond = general warning ahead.
• Pentagon = school zone/crossing.
• Round shape = railroad crossing.
• White rectangle, black text = regulatory rule (e.g., speed limit).
• Orange rectangle = construction/work zone.
• Green/blue rectangle = directional/informational guide sign.

Idaho's own test groups signs into regulatory, warning, work zone, and guide categories — know the category, not just the picture.

Right-of-way in one breath

• First to arrive at an uncontrolled intersection goes first; tie goes to the driver on the right.
• Left turns yield to oncoming traffic unless you have a dedicated arrow.
• Pedestrians in a crosswalk always have the right-of-way over turning cars.
• Emergency vehicles with lights/sirens on: pull right, stop, let them pass.
• Vehicles already in a roundabout have priority over vehicles entering.
• Merging traffic yields to traffic already in the lane.

Top traps

• Assuming a green light beats a pedestrian in the crosswalk — it doesn't.
• Treating the posted speed limit as safe in rain, snow, ice, or fog — reduce speed below it.
• Mixing up yield (triangle) and warning (diamond) shapes — yield is about right-of-way, diamonds are general hazard warnings.
• Forgetting that fatigue counts as impairment — drowsy driving slows reaction time like alcohol can.
• Not budgeting your error margin — 6 missed questions out of 40 disappears fast if you're shaky on sign shapes alone.
• Assuming a failed real test is a quick redo — it's a mandatory 3-day wait plus another $5.00 fee, so treat every practice run seriously.
• Overlooking that a four-way stop uses the same first-to-arrive, yield-to-the-right logic as an uncontrolled intersection once everyone has stopped.