Google has a new interesting search called Ngrams. You can see how often a search term occurs in books Google has scanned, starting from 1500! Quite amazing. I did a search for a "Hydrogen Car" and found out that in Popular Science Magazine from 1974 they have an article about a dual fuel Hydrogen car. Quite amazing. Looks very similar to what United Nuclear is doing currently in the US but this technology has been available already from 1970s.