Tim May, a member of the innumerate majority, was quoted by Chris in USMA 9391. I don't know of any country that has gone metric by popular vote; it is always a government decision imposed on a reluctant or indifferent population. The British government decided that Britain should go metric in 1965 after a request from the Confederation of British Industries that Britain do so because half of British exports were going to metric countries, and that this share of exports was increasing. People who are thoroughly familiar with both systems consider that the metric system is simpler and more efficient. Statisical studies of engineering design work in Britain and the USA have found that there is a significant reduction in design time when metric units are used instead of inches, pounds, etc. Tim May might reply "Let the engineers use the metric system if they want to, but let us ordinary people use the units that we have used for hundresds of years". The answer is that is is costly to use two systems; remember the Mars Climate Orbiter.
