<P> Experiments have been conducted on automating cars since at least the 1920s; promising trials took place in the 1950s and work has proceeded since then . The first self - sufficient and truly autonomous cars appeared in the 1980s, with Carnegie Mellon University's Navlab and ALV projects in 1984 and Mercedes - Benz and Bundeswehr University Munich's Eureka Prometheus Project in 1987 . Since then, numerous major companies and research organizations have developed working prototype autonomous vehicles including Mercedes - Benz, General Motors, Continental Automotive Systems, Autoliv Inc., Bosch, Nissan, Toyota, Audi, Volvo, Vislab from University of Parma, Oxford University and Google . In July 2013, Vislab demonstrated BRAiVE, a vehicle that moved autonomously on a mixed traffic route open to public traffic . </P> <P> As of 2013, four U.S. states have passed laws permitting autonomous cars: Nevada, Florida, California, and Michigan . In Europe, cities in Belgium, France, Italy and the UK are planning to operate transport systems for driverless cars, and Germany, the Netherlands, and Spain have allowed testing robotic cars in traffic . </P>

How long have they been testing self driving cars
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