<P> A speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle . Now universally fitted to motor vehicles , they started to be available as options in the 1900s , and as standard equipment from about 1910 onwards . Speedometers for other vehicles have specific names and use other means of sensing speed . For a boat , this is a pit log . For an aircraft , this is an airspeed indicator . </P>
what type of speed does a speedometer measure
speed of a vehicle