Just a sample of what a metric speed sign might look like in the UK...
Designed it myself using the standard font used on British Road signs. (Traffic medium for the inquiring minds)
80 km/h = 50mph exactly
Won't this look so nice on a road?.. or generally km/h signs?
80 km/h seems so much faster than 50 mph!
And it would be understood by far more people.
The government simply needs to realise this!