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Oklahoma driving lesson · Driving Tips and Emergencies

Floods and what to do after a crash

A 3-minute lesson from the Oklahoma course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.

Read time
3 minutes
Course unit
Driving Tips and Emergencies
Checkpoint questions
6
Source pages
62, 63

Moving water is far stronger than it looks, and a car becomes buoyant fast. Most vehicles will float in just 2 feet of water, even SUVs. If you meet a flooded road: Turn Around, Don't Drown.

Flood dynamics

Flood dynamics
FactValue
Weight of waterAbout 62.4 pounds per cubic foot
Typical flow speed6 to 12 miles an hour
Sideways force per foot of water rise500 pounds
Water displaced per foot of rise1,500 pounds (car weighs that much less)
Depth at which most vehicles float2 feet (24 inches)
Handbook p. 62 ↗
Vehicle buoyancy in flood water (lateral forces)
A car swept along by floodwater

Flood safety rules:

  • Cars can easily stall in water and be carried away in any current
  • Most vehicles will be swept away by less than 2 feet (24 inches) of running water
  • Don't try to cross a flooded road or stream, or drive into flowing water
  • Don't drive around barricades at low-water crossings
  • Be especially vigilant at night or on unfamiliar roads
  • Remember roadbeds beneath the water may have been washed away
Handbook p. 62 ↗
6 inches

Water that may make you lose control of your vehicle, and fast-moving water that can knock you off your feet

Handbook p. 63 ↗

Know the rule

Observe water level indicators at low-water crossings. If you abandon your vehicle, respect the force of the water.

Handbook p. 63 ↗

If you're in a collision that results in death, injury or property damage, stay calm and follow the steps below.

After a crash:

  • Stop and call 911 or local law enforcement
  • Turn on hazard lights
  • Get help for anyone hurt, but DON'T move an injured person unless it's a life-or-death necessity
  • If the crash is minor and your vehicle blocks traffic, move it or have it moved
  • Exchange vehicle, witness and driver information (name, address, phone, license, registration, insurance)
  • Take photos
  • Don't blame others, accept blame or discuss the accident; answer officers truthfully and calmly
Handbook p. 63 ↗

Know the rule

If you hit a parked car or property and can't find the owner, leave the driver's and owner's name and address and your insurance verification information where the owner will find it.

Handbook p. 63 ↗

Know the rule

The investigating officer completes a report. Contact your insurance company as soon as possible to report the accident.

Handbook p. 63 ↗

Put it into practice

After a minor fender bender in a busy lane, no one is hurt. Call police, turn on your hazards and move the cars out of traffic. Exchange information and take photos. Don't argue over fault; tell the officer calmly what happened.

Check your understanding

Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.

About how much water can make most vehicles float away?
  1. 2 feet (24 inches)
  2. 6 inches
  3. 4 feet
  4. 1 foot

Answer: 2 feet (24 inches)

Most vehicles, even SUVs, will float in about 2 feet of water.

Handbook p. 62 ↗
What is the first thing you should do after a crash involving injury?
  1. Stop and call 911
  2. Move all vehicles immediately
  3. Exchange insurance information first
  4. Take photos before anything else

Answer: Stop and call 911

Stop and call 911 or local law enforcement first.

Handbook p. 63 ↗
Should you move an injured person after a crash?
  1. Yes, always move them to the roadside
  2. No, unless life-or-death
  3. Only if you're a medical professional
  4. Yes, to make room for other traffic

Answer: No, unless life-or-death

Do not move an injured person unless it's a life-or-death necessity.

Handbook p. 63 ↗
If you encounter a flooded roadway, you should turn around instead of driving through it.
  1. True
  2. False

Answer: True

Turn Around, Don't Drown is the rule for flooded roadways.

Handbook p. 63 ↗
About how much lateral force does floodwater apply to a stalled car for each foot it rises?
  1. About 100 pounds
  2. About 500 pounds
  3. About 2,000 pounds
  4. About 50 pounds

Answer: About 500 pounds

For each foot the water rises, about 500 pounds of lateral force is applied to the car.

Handbook p. 62 ↗
After a minor crash where your car is blocking traffic, what should you do?
  1. Leave it where it stopped until police arrive
  2. Wait for a tow truck before moving it
  3. Move it out of the way if you're able to
  4. Leave it but turn off the engine

Answer: Move it out of the way if you're able to

If a crash is minor and your vehicle blocks traffic, you must move it or have it moved.

Handbook p. 63 ↗
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