Probably just a historical quirk. Around here, most distances are measured in meters, however people's height is usually expressed in feet and inches. Even weirder is when talking about air temperature, we always use Celsius, yet water temperature is often talked about in Fahrenheit. I've often heard people say things like ''It's a good day for a swim. It's 25 degrees out and the pool's at 81"!Always wondered how you Brits function with such mixed units... You buy your fuel in litres, yet calculate your economy in imperial gallons and track speed and distance in miles.