Miles per hour be used to express the speed of delivery of a ball in sporting events such as cricket, tennis and baseball. Miles per hour Miles per hour (abbreviated mph, MPH or mi/h) is an imperial and United States customary unit of speed expressing the number of statute miles covered in one hour. It is used in the United States, United Kingdom and many Commonwealth nations, particularly in the Caribbean region. Speed limits and road traffic speeds are given in miles per hour in the following jurisdictions (elsewhere kilometers per hour are used): Road traffic speeds in other countries are indicated in
Kilometres per hour in 1810, and the compound unit of speed "kilometers per hour" was in use in the US by 1866. "Kilometres per hour" did not begin to be abbreviated in print until many years later, with several different abbreviations existing near-contemporaneously. With no central authority to dictate the rules for abbreviations, various publishing houses have their own rules that dictate whether to use upper-case letters, lower-case letters, periods and so on, reflecting both changes in fashion and the image of the publishing house concerned. For example, news organisations such as Reuters and The Economist require "kph". In Australian unofficial usage, km/h