You need 80% to pass the Iowa permit knowledge test; the official Iowa sources we checked do not state a fixed question count. Official source. Page updated 2026-10-19.
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Key Iowa DMV rules and numbers
These are key rules and numbers from the Iowa handbook, a few per topic so they fit on one printed page. We favor rules that state a specific number. Every fact below comes from our free Iowa DMV practice test question bank, which has 500 questions across 9 topics, checked against the Iowa handbook (last verified 2026-09-07).
Speed limits
- A residential district has a general unposted limit of 25 mph, and a school district uses that same figure. (Handbook, p. 42)
- Iowa lists 45 mph as the general limit for an unposted suburban district. (Handbook, p. 42)
- The manual gives rural interstate highways a general unposted limit of 70 mph. (Handbook, p. 42)
- The interstate system has a minimum speed of 40 mph in the manual. (Handbook, p. 42)
- Iowa's general limit on unsurfaced secondary roads is 50 mph from sunset until sunrise, and trucks are held to 50 mph on secondary roads at any time of day. (Handbook, p. 42)
Right of way
- School buses and vehicles carrying hazardous materials must stop within 15 to 50 feet of railroad tracks before crossing, unless a police officer or a highway traffic signal directs traffic to proceed or the crossing is marked as exempt. (Handbook, p. 12)
- Iowa allows a right turn on a red light unless a NO TURN ON RED sign is posted, but only after a complete stop and only while yielding to all other traffic. (Handbook, p. 43)
- A driver emerging from a driveway, alley, or roadside must yield to vehicles already using the main road. (Handbook, p. 19)
- The manual names failure to yield the right-of-way as Iowa's number one cause of traffic-related fatalities. (Handbook, p. 18)
- A left-turning driver must yield to oncoming cars that are proceeding straight ahead. (Handbook, p. 19)
Alcohol and DUI
- For the general adult OWI definition, Iowa uses a BAC of .08 or higher. (Handbook, p. 37)
- An underage driver with a BAC at .02 or above but below .08 faces a minimum 60-day revocation under the manual. (Handbook, p. 37)
- The underage revocation minimum rises to 180 days when the BAC is .08 or more. (Handbook, p. 37)
- Iowa still revokes driving privileges for at least 180 days after operating while intoxicated, even when criminal court does not produce an OWI conviction. (Handbook, p. 37)
- The manual says offenders under age 18 are not eligible for a temporary restricted license while their license is revoked for OWI. (Handbook, p. 37)
Signals and markings
- A reflective orange triangle marks a vehicle traveling at 35 mph or less. (Handbook, p. 11)
- Iowa law requires a turn signal at least 100 feet before a turn when the speed limit is 45 mph or less, and at least 300 feet before the turn when the limit is faster than 45 mph. (Handbook, p. 43)
- The side with the dashed yellow line may use the opposing lane to pass, but only after the driver confirms that the maneuver is safe. (Handbook, p. 15)
- A solid yellow line marks the side where passing is prohibited. (Handbook, p. 15)
- A steady yellow signal marks a transition and calls for a judgment about stopping safely. (Handbook, p. 11)
Parking
- When parking on a roadway beside a curb, Iowa's manual says to park within 18 inches of the curb or closer. (Handbook, p. 21)
- Iowa prohibits parking closer than 10 feet from a stop sign. (Handbook, p. 21)
- Iowa prohibits parking closer than 20 feet from a fire station entrance. (Handbook, p. 21)
- Iowa makes drivers responsible for keeping a parked vehicle from becoming a hazard, and that includes the moment you open the door. (Handbook, p. 21)
- Iowa bans parking on any bridge outside city limits and in highway tunnels. (Handbook, p. 21)
Safe driving
- The manual gives a minimum following distance of 500 feet behind an emergency vehicle using lights and sirens. (Handbook, p. 19)
- For a driver meeting the bus from the front in the described two or three lane setting, amber warning lights require slowing to no more than 20 mph and preparing to stop. (Handbook, p. 20)
- Iowa says a school-bus passing violation may result in a driver's license being suspended for up to 180 days. (Handbook, p. 20)
- Iowa requires both headlights from sunset to sunrise and whenever visibility is 500 feet or less. (Handbook, p. 49)
- Horse-drawn vehicles normally travel slowly and may display a reflective orange triangle, the Iowa sign for a vehicle moving 35 mph or less. (Handbook, p. 9)
Road signs
- A stop sign requires a full stop and waiting until crossing vehicles and the crosswalk are clear before proceeding. (Handbook, p. 8)
- A yield sign directs the driver to slow down and yield the right of way to traffic in the intersection being crossed or the roadway being entered. (Handbook, p. 8)
- The Iowa manual defines a one-way sign as meaning traffic moves only in the direction of the arrow. (Handbook, p. 8)
- The wrong-way sign indicates that a driver made a wrong turn and entered a lane of oncoming traffic. (Handbook, p. 8)
- Iowa's manual lists exit ramps, crossovers on divided roadways, and numerous locations on one-way roads as places where a do not enter sign may appear. (Handbook, p. 8)
Laws and paperwork
- For trucks on secondary roads, Iowa applies the 50 mph limit at any time of day. (Handbook, p. 42)
- Applicants under 18 must show successful completion of an Iowa-approved driver's education course. (Handbook, p. 5)
- If you are distracted and cause the death of another person, the manual says you could face more than $1,000 in fines, have your license suspended, and depending on the circumstances be charged with vehicular homicide. (Handbook, p. 36)
- Iowa Code section 805.8A sets the scheduled fines for these violations. (Handbook)
- Iowa requires at least one red light on the back of the vehicle, visible for at least 500 feet, plus two headlights and a white light for the rear license plate. (Handbook, p. 24)
Emergencies
- Iowa prohibits parking closer than 50 feet from a railroad crossing. (Handbook, p. 21)
- Iowa requires police notification when a crash involves injury or death to another person or property damage exceeding $1,500. (Handbook, p. 63)
- If a vehicle stalls on the tracks with a train coming, Iowa says to get everyone out immediately and move away from the tracks at a 45-degree angle, in the direction of the approaching train. (Handbook, p. 12)
- The Iowa manual warns that as little as 6 inches of water may sweep away a vehicle, including SUVs and pickups. (Handbook, p. 60)
- Iowa law requires reporting a crash that involves injury or death or property damage of more than $1,500. (Handbook, p. 63)
Want the reasoning behind these rules? Study the handbook, chapter by chapter, in 21 short lessons quoted from the Iowa manual.
Signs
Sign shape and color carry meaning before you even read the words. A red octagon always means stop, a red-bordered triangle pointing down means yield, and yellow diamonds warn of a hazard ahead. For every sign image used in our practice test, with the exact meaning and explanation, see the full road sign glossary.
Keep studying
This cheat sheet is a summary, not a substitute for practice. Test yourself with the free Iowa DMV practice test, which explains the reasoning behind every answer, or see Iowa DMV facts and fees before test day.