How many times have you found yourself suddenly confronted by a speed limit sign, then in a panic you look at the bouncing speedometer pointer and immediately start doing math in your head. "Let's see ...

Q: The top speed on my car speedometer is 130 mph, yet the car cannot go anywhere close to that speed. So why does the speedometer go so high? Is it a marketing gimmick or is there some other reason?

Motorists may be unfairly booked for speeding because their speedometers are underestimating how fast they're travelling, says an Australian researcher. Short drivers in cars with poor tyres or with a ...