For more than 150 years TAG Heuer has been producing quality watches. The company was founded by Edouard Heuer and his sons Jules-Edouard and Charles-Auguste and was the first company to produce a mechanical stopwatch -- the Mikrograph -- that is accurate to 1/100th of a second. Today the company continues to produce quality watches. One such model is the Carrera Automatic Chronograph Tachymetre. The watch has an outer tachymeter ring that is designed to "calculate your average speed over a distance of 1 mile" according to the TAG Heuer owner's manual. This can be used for any moving object, such as a bike, car or boat.
Measure off a distance of 1 mile and mark it with traffic cones or some other identifying object.
Press the chronograph start/stop button on the watch when the vehicle passes the first cone. The start button is located at approximately the 2:00 position on the side of the watch.
Press the chronograph start/stop button again as the vehicle crosses the 1-mile marker.
Look at the watch face and see where the second hand has stopped. Notice where on the outer tachymeter ring the second hand is pointing to. This is the speed. For example, if the second hand is pointing at the 6:00 position, look to the outer tachymeter ring and you will see the number "120." This indicates that the car travelled that distance at 120 miles per hour.