Engines of Our Ingenuity

No. 1173:
A SINKING AUTOMOBILE

by John H. Lienhard

Click here for audio of Episode 1173.

Today, thoughts about thinking while I'm drowning. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Crossing the campus on the way to the radio station, I run into my colleague John Hunsucker. "What's new with the Heimlich maneuver?" I ask him. Hunsucker has been teaching lifeguards to use the Heimlich grip to flush water out of drowning victims. His method has already saved a lot of lives. But today his mind is on other things. "John," he says, "suppose your car goes into the bayou. How do you get out of it once you're in the water?"

I figure I'm pretty cool under pressure. I tell how I'd open the door right away or kick out a window and swim for it. Hunsucker blocks all my ideas. "You think you're strong enough to kick out a car window?" "Did you remember the seat belt?" I'm getting uncomfortable. I feel cold water rising as I guess the wrong moves.

In the first place, many cars roll down embankments and enter water with windows closed and intact. A sealed car floats two to four minutes. We have two minutes to get everyone unbelted and decide what to do. Meanwhile, water leaks through the engine fire wall and the heavier front of the car sinks first. Our instinct is to follow the air bubble into the back seat where we can't get out.

The car goes down nose first and often flips onto its back. Since seat belts don't retract under water, it's easy to tangle in them. Electric window controls fail after about five minutes. Once we're on the bottom, we get disoriented. We have to go to the floor above to breathe, and the window below to get out.

If we still have our wits about us while the car's afloat, we have to get everyone ready before we open the window. Once we do, water floods in and we have maybe 20 seconds to get out. But if the window's under water, pressure can hold it shut. Then we have to crack the door. Once we do that, our time is really limited.

Hunsucker says 350 people die this way every year, far fewer than die by, say, tobacco use or drunk driving. But like those deaths, so many of these could be prevented by thinking ahead.

Once I only buckled my seat belt because I had to. Then one actually saved me from serious injury. That's why I now force myself through the uncomfortable process of thinking through sinking-car scenarios -- feeling fear I'd rather not think about.

The chances are slim that I'll ever face that situation. But Hunsucker tells me about a man who got out of a sinking car -- then stood on its roof as it sank, desperately trying to break in the rear window to get his wife out as well. That's a horror no one should have to carry.

This is no place where we want to rely on instantaneous invention. This is a problem that each of us needs to solve ahead of time.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Donohue, W. A., Michigan State Police, Operation Star: Submerged Transportation Accident Research. Searchlines, Vol. 10, No. 1, January/February 1993.

Donohue, W. A., Operation S.T.A.R.: Submerged Transportation Accident Research. Final Report, Michigan Department of State Police. East Lansing, MI: Department of Communication, Michigan State University.

Hunsucker, J. L., The Heimlich Maneuver and Drowning. Splash, Vol. 16, No. 5, May/June 1996.

For his counsel and for source materials, I am grateful to Professor John Hunsucker, Industrial Engineering Department, University of Houston, Houston, TX, 77204-4812, 713-743-4194. Hunsucker is presently working on the formulation of escape protocols for sinking vehicles. He makes the point that fear makes rational action very difficult in a sinking car. He recommends the following minimum protocol for use if your car is still afloat.

  1. Release your seat belt (but not until you land. You won't survive the sinking car if you have not first survived the accident that put you in the water.)
  2. Undo the door locks.
  3. Get any passengers out of their belts and ready to escape.
  4. Roll down the windows.
  5. Get any children out the window first.
  6. Follow them out.
  7. Opening the door is a last resort. Open it only if you cannot, for some reason, get a window down.



The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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