SARTRE is short for Safe Road Trains for the Environment, and it’s a project Volvo is working on jointly with Ricardo UK Ltd, Applus+ Idiada, Tecnalia Research & Innovation, and a couple of others research institutes. They just made a giant leap forward, as the first ever autonomous road train debuts successfully on the public roads just outside Barcelona. The road train included a Volvo XC60, a Volvo V60 and a Volvo S60 plus one truck automatically driving in convoy behind a lead vehicle. It did 200 km and returned safely without a glitch. This might sound all very fancy, but if you think about it, it’s not that outlandish. The cars were driving themselves alright, but they were following a lead vehicle driven by a human driver. So all they needed was adaptive cruise control to accelerate and brake in accordance to the speed of the lead car. That said, it’s not that simple either! The steering and the precision of the task is where things get kinda complicated. The cars has wireless communication with each other so they could mimic  lead vehicle using Ricardo autonomous control – accelerating, braking and turning in exactly the same way as the leader. Now might be thinking what’s the benefit of such a system? Volvo says it can improve traffic safety, reduce environmental impact and – thanks to smooth speed control – cut the risk of traffic tailbacks. It would also be of big help to the dealerships when they want to send a couple of cars to, say, a showroom. They just put a driver in the lead vehicle and the rest of fleet just follows him like sheep! Looks like Volvo finally got this radar-based thing right. Their first attempts, especially with auto braking systems, where all flawed.