The Vienna Convention doesn’t come up very often when discussing cars. This treaty’s main purpose is to codify the notion of diplomatic immunity, but it has other implications that have a significant bearing on the introduction of autonomous vehicles to our roads.A change to the Vienna Convention on road traffic was passed in 2014 that crucially amended the statement that a driver should be in control of a vehicle at all times. For autonomous vehicles and their developers, this was a watershed moment.Over here in the UK, this news was perhaps less momentous as we had signed but not ratified the Vienna Convention in the first place, so were not strictly bound by it. While the UK has been happy to go along with diplomatic immunity, it wasn’t so bothered with the bit about keeping your hands on the steering wheel.Consequently, the UK has been among the front-runners in designing and developing connected and autonomous vehicle (CAV) technology. It’s also why the UK has been one of the very first countries to allow road trials of CAVs, including now heavy goods vehicles.Real benefitsThe benefits are clear. It’s not about the driver being able to catch up on sleep while on the commute to work but about reducing collisions, saving lives and lowering fuel use and emissions.With the recent announcement of HGV CAV trials in the UK, it has refocused attention on one of the major tenets of autonomous vehicle use: platooning.This is where vehicles travel in a closely packed convoy on the motorway to minimise the amount of road space they occupy and improve efficiency through better aerodynamic effect. It’s the same idea as cyclists in the Tour de France slipstreaming each other to achieve the same speed for less effort.What happens if an autonomous vehicle does break the law? Who would be to blame?Driving too closely to the vehicle in front is one of the most common causes of collisions in the UK, combined with driver error and inattention. Autonomous vehicles are being designed to factor out the inattentiveness of the human and, by synchronising acceleration and braking of the vehicles in the platoon, technology can make this safe.