Vehicle Checks, Seat Belts and Child Restraints

Key points

1. Check tire pressure with a gauge when the tires are cold.

   Source: Handbook p. 24

   “Check tire air pressure with an air pressure gauge when the tires are cold.”
   Iowa Driver's Manual, Handbook p. 24

2. If the tread does not reach the top of Lincoln's head on a penny, replace the tire.

   Source: Handbook p. 24

   “If the tread does not come at least to the top of Lincoln’s head, the tire is unsafe and should be replaced.”
   Iowa Driver's Manual, Handbook p. 24

3. Windows beside the driver and the windshield must let at least 70 percent of the light through.

   Source: Handbook p. 24

   “Iowa law requires tinted windshields and windows to the immediate right or left of the driver to allow at least 70 percent of the light through.”
   Iowa Driver's Manual, Handbook p. 24

4. Do not hang things from your rearview mirror or clutter the windshield with decals.

   Source: Handbook p. 24

   “Do not hang things from your rearview mirrors or clutter up the windshield with decals.”
   Iowa Driver's Manual, Handbook p. 24

5. Sit at least 10 inches from the steering wheel air bag.

   Source: Handbook p. 25

   “There should be at least 10 inches between the steering wheel and your chest, with the air bag pointing at your chest.”
   Iowa Driver's Manual, Handbook p. 25

6. Seat belt violations carry fines up to $50 per passenger and $100 per passenger under 18.

   Source: Handbook p. 34

   “The violation of this law is punishable with up to a $50 fine per passenger and $100 per passenger under 18.”
   Iowa Driver's Manual, Handbook p. 34

7. A child under 1 and under 20 pounds must ride rear facing; under 6, in a child restraint system.

   Source: Handbook p. 35

   “A child under one year old and weighing less than 20 pounds must be secured in a rear-facing child restraint system. • A child under six years old must be secured in a child restraint system (a safety seat or booster seat, not a seat belt).”
   Iowa Driver's Manual, Handbook p. 35

8. Ages 6 to 18 need a child restraint or seat belt in every seat, front and back.

   Source: Handbook p. 35

   “A child from the age of six up to the age of 18 must be secured in a child restraint system or by a seat belt, in all seating positions (front and back).”
   Iowa Driver's Manual, Handbook p. 35

Numbers to know

3 questions from the Iowa practice test

1. 1. When should tire pressure be checked, according to the Iowa manual?

   1. Right after a long highway drive
   2. With an air pressure gauge when the tires are cold
   3. Once a year
   4. Only at a repair shop
   Show answer

   With an air pressure gauge when the tires are cold. Check tire air pressure with an air pressure gauge when the tires are cold, because driving heats the air inside and raises the reading. The recommended pressure is commonly listed on a sticker inside the driver's door or in the owner's manual. Worn, bald or unbalanced tires and under or over inflation all affect handling and stopping, so the check is a regular habit, not a yearly or shop only task.

2. 2. How does the Iowa manual say to check tire tread with a penny?

   1. Insert the penny tail first and look for the memorial
   2. Measure the tread with the penny's edge
   3. Insert the penny head first; if the tread does not reach the top of Lincoln's head, replace the tire
   4. Roll the penny across the tire
   Show answer

   Insert the penny head first; if the tread does not reach the top of Lincoln's head, replace the tire. Check tire tread with a penny by sticking the penny into the tread head first. If the tread does not come at least to the top of Lincoln's head, the tire is unsafe and should be replaced. Shallow tread cannot channel water away and invites hydroplaning and longer stops. The test takes seconds and works on every tire, so do it along with the monthly pressure check.

3. 3. What does the Iowa manual say about hanging items from the rearview mirror?

   1. It is fine if the item is small
   2. Only air fresheners are allowed
   3. Do not hang things from the mirror or clutter the windshield with decals
   4. Items may hang below the dash line
   Show answer

   Do not hang things from the mirror or clutter the windshield with decals. Keep your view unobstructed. The manual says not to hang things from your rearview mirrors or clutter up the windshield with decals, because even a small dangling object blocks part of the view and draws the eye. Window tint must also meet the state standards. A clear windshield and mirrors are part of the vehicle checks the manual expects before every drive.

Source: the Iowa Driver's Manual, Chapter 3: Preparing to Drive. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.