Night Driving, Bad Weather and Floods

Key points

1. Headlights are required from sunset to sunrise or whenever visibility is 500 feet or less.

   Source: Handbook p. 49

   “Iowa law requires the use of both headlights from sunset to sunrise or whenever visibility is 500 feet or less”
   Iowa Driver's Manual, Handbook p. 49

2. Do not use cruise control in wet or slippery conditions.

   Source: Handbook p. 60

   “DO NOT USE CRUISE CONTROL IN WET OR SLIPPERY CONDITIONS.”
   Iowa Driver's Manual, Handbook p. 60

3. In fog, drive slower and increase your following distance to 5 or 6 seconds.

   Source: Handbook p. 60

   “Drive slower than normal and increase your following distance to five or six seconds.”
   Iowa Driver's Manual, Handbook p. 60

4. If you might hydroplane, slow down.

   Source: Handbook p. 60

   “If you can see deep water on the road, reflections on the pavement, or if the car ahead leaves no tracks on the water, your car could hydroplane. Slow down.”
   Iowa Driver's Manual, Handbook p. 60

5. As little as 6 inches of water may sweep away a vehicle, including SUVs and pickups.

   Source: Handbook p. 60

   “As little as 6 inches of water may sweep away a vehicle, including SUVs and pickups.”
   Iowa Driver's Manual, Handbook p. 60

6. If stalled in floodwater, abandon the vehicle and move to higher ground.

   Source: Handbook p. 60

   “If your vehicle is stalled in floodwater, abandon the vehicle and move to higher ground.”
   Iowa Driver's Manual, Handbook p. 60

7. If your car is submerged, wait for it to fill with water; then the doors open more easily.

   Source: Handbook p. 60

   “Wait for the vehicle to fill with water. Once the vehicle is full, the doors are easier to open.”
   Iowa Driver's Manual, Handbook p. 60

8. Stopping distances can be 10 times greater in ice and snow.

   Source: Handbook p. 61

   “Stopping distances can be 10 times greater in ice and snow.”
   Iowa Driver's Manual, Handbook p. 61

Numbers to know

3 questions from the Iowa practice test

1. 1. Your vehicle stalls in floodwater on an Iowa road. What does the manual say to do?

   1. Stay inside and wait for help
   2. Restart the engine and drive on
   3. Abandon the vehicle and move to higher ground
   4. Open the windows and wait
   Show answer

   Abandon the vehicle and move to higher ground. Do not stay in a flooded vehicle. If your vehicle is stalled in floodwater, abandon it and move to higher ground, because water can rise quickly and carry the vehicle away. If the car is swept into water and submerged, remain calm, wait for it to fill with water so the doors open, then hold your breath and swim to the surface. Restarting a flooded engine does not work and wastes time.

2. 2. Your car is swept into water and submerged in Iowa. What does the manual say about opening the doors?

   1. Wait for the vehicle to fill with water; once full, the doors are easier to open, then hold your breath and swim to the surface
   2. Break the windshield first
   3. Wait for rescuers to open them
   4. Force the doors open immediately
   Show answer

   Wait for the vehicle to fill with water; once full, the doors are easier to open, then hold your breath and swim to the surface. If your car is swept into the water and submerged, remain calm and wait for the vehicle to fill with water. Once the vehicle is full, the pressure equalizes and the doors are easier to open; hold your breath and swim to the surface. Forcing a door against the water pressure early rarely works, and waiting for rescuers wastes the air you have. The best defense is never driving into floodwater.

3. 3. What is the safest response when water on the road causes your vehicle to hydroplane?

   1. Accelerate until the tires cut through the water
   2. Brake hard and turn sharply
   3. Slow down by easing off the accelerator
   4. Swerve onto the shoulder immediately
   Show answer

   Slow down by easing off the accelerator. Hydroplaning occurs when water deeper than the tire tread reduces friction and can cause loss of control. The manual's immediate instruction is to slow down, which supports easing off the accelerator while keeping steering smooth. Hard braking, a sharp turn, or an abrupt shoulder swerve can worsen the loss of grip. Accelerating adds speed without restoring traction. Watch for deep water, reflections on pavement, or a car ahead leaving no tracks. Those clues mean reduce speed early and avoid sudden inputs until the tires regain contact with the road.

Source: the Iowa Driver's Manual, Chapter 5: Night Driving and Inclement Weather. 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.