what is the difference between km/h and mph ?

[getting355]

how do i get mph to km/h >

[Kine_ESP]

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. While kilometres per hour is more commonly used worldwide, miles per hour remains the standard unit used for speed limits in some countries, and to express speeds generally, in many countries throughout the world.

1 mph = 1,609344 km/h (exactly).

- Wikipedia[en.wikipedia.org]

Signs of speed limit in USA (and The Crew, of course) are in mph. (example: sign "50").

[J3SQ]

You can change it in the game options, imperial units gives you mph while metric units gives you kmh.