Miles per hour

Road traffic

Speed limits and road traffic speeds in some countries and territories are indicated in miles per hour, as follows (all other countries use kilometers per hour):

• the United Kingdom^[1] and its overseas dependencies:
  • British Virgin Islands^[2]
  • the Cayman Islands^[3]
  • the Falkland Islands^[4]
  • Saint Helena, Ascension and Tristan da Cunha^[5]
  • Turks & Caicos Islands^[6]
• the United States^[7] and its overseas dependencies:
  • American Samoa^[8]
  • Guam^[9]
  • the Northern Mariana Islands^[10]
  • the U.S. Virgin Islands^[11][12]
  • Puerto Rico
• The Bahamas^[13]
• Belize^[14]
• Dominica^[15]
• Grenada^[16]
• Samoa^[17]
• St. Lucia^[18]
• St. Vincent & the Grenadines^[19]
• St. Kitts & Nevis,^[20]
• Antigua & Barbuda

Road traffic speeds in other countries are indicated in kilometres per hour, while occasionally both systems are used. For example, in Ireland, a judge considered a speeding case by examining speeds in both kilometres per hour and miles per hour. The judge was quoted as saying the speed seemed "very excessive" at 180 km/h but did not look "as bad" at 112 mph; a reduced fine was still imposed on the speeding driver.^[21]

Rail networks

Miles per hour is the unit also used in the Canadian rail system,^[22] which uses km/h on roads.

Nautical and aeronautical usage

Nautical and aeronautical applications favour the knot as a common unit of speed. (One knot is one nautical mile per hour, with a nautical mile being exactly 1,852 meters or about 6,076 feet.)

Other usage

In some countries mph may be used to express the speed of delivery of a ball in sporting events such as cricket, tennis and baseball.