If you guys could please go ahead and switch to the metric system it would be a big help in forums as I would have to do less conversion in my head as I read.
In NZ the switch to the Imperial system to metric was in 1976, also from Pounds to Dollars (NZD) in 1967.
I don't think there were really any problems, maybe a few confused older folk. So I think it's been demonstrated around the world that it can be done.
I'm sure there were a few cases of people doing 100mph in a 100kph zone.
I've always found it slightly ironic that USA clings to the British system (modified a little), yet I live in a British Commonwealth member nation and we made the switch to metric without flinching. The difference being New Zealand is a young nation, things are easy to administrate - we have about the size and population of a single US state.