A friend of mine says that the speedometers on American...

Dear Car Talk

Dear Car Talk | Apr 01, 1994

Dear Tom and Ray:

A friend of mine says that the speedometers on American made cars are set five MPH under the actual speed the vehicle is travelling. For example, if she is driving 60 MPH according to the speedometer, she is REALLY only going 55 MPH. Foreign cars, however, according to her, are set correctly and show the actual speed the car is going. I find this hard to believe. Is she right?

TOM: Nancy, your friend is wacko.

RAY: I can speak from personal experience about the accuracy of American car speedometers....having been stopped by the state police in 41 of the 50 states. My experience is that they're accurate to within about a mile an hour. When they stop me for doing 72, I'm usually doing 72.

TOM: Of course, that's not what he tells the trooper.

RAY: Oh no. I always remind him that it's a well known fact that American car speedometers are off by 10 MPH, so I was really only doing 62!

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