1955 BMW BMW Isetta 250/300

Although universally admired, BMW’s luxury cars were selling slowly. So, the decision to acquire the licence to build the Isetta proved to be an inspired piece of lateral thinking by BMW management. The Isetta was just what was needed, and as the effects of the Suez Crisis started to hit, and petrol became a rare commodity, suddenly the motorcycle engine car that could achieve 50mpg all day long made a great deal of sense. Front-hinged door and three wheeled handling were questionable, but buyers loved them...for a while.

Information from Octane Magazine.