Project SARTRE (or Safe Road Trains for the Environment) has successfully completed a 125 mile test involving three autonomous cars on public roadways in Spain. What differentiates SARTRE from Google's driverless car is that SARTRE consists of a caravan of autonomous vehicles with a leading car driven by a professional driver. Each vehicle behind the leader follows the one in front of it using a wireless network accompanied by a litany of cameras, radar sensors, and laser guidance systems that judge speed and direction. The goal of project, which is being funded by the European Commission, is to increase motorway safety and environmental conservation without having to heavily modify the existing road systems.

This test represents a major milestone for the SARTRE project, which was started in 2009 and until this point has only been tested on Volvo's private testing tracks in Sweden. The test was done at around 50mph with a 20 foot gap between cars, and the European Commission (EC) estimates that cars driving in this autonomous caravan can reduce up to 20% of fuel emissions versus driving individually. The SARTRE project is also hoping to save lives — by having a fresh, experienced driver leading the caravan, motorists following behind are free to check their phones or read a book without being distracted from the road. There isn't a firm date for the completion of the project, but a successful public test is certainly a good start.