Miles per hour (MPH) is a unit of speed primarily used in the United States and a few other countries. Canada officially uses kilometres per hour (km/h) for all traffic signs and speed regulations since adopting the metric system in the 1970s. However, Canadians may encounter MPH on American vehicles' speedometers, when travelling to the United States, or in American media. The conversion is approximately 1 mile equals 1.6 kilometres, so 60 MPH equals roughly 100 km/h. Understanding the difference helps Canadian drivers who travel internationally and prevents confusion when encountering American speed references.