HANDS OFF

Platoons of self-driving trucks are one rule change away from being legal in the UK

Efforts to make self-driving vehicles commonplace don’t just come down to automotive technology. They also will require changing the rules that govern the roads.

The latter is a focus now in the UK, where the government has proposed regulatory changes that would smooth the way for a form of self-driving truck technology called “platooning.” That’s when trucks are connected by wireless technologies, like wifi, to follow a manned lead vehicle in a tight convoy, saving fuel and potentially manpower. In April, dozens of trucks drove thousands of kilometers across Europe in a landmark trial of the technology.

Truck platooning in the UK would be allowed with tweaks to one regulation, Highway Code Rule 126, which says that drivers must leave a two-second gap between their vehicle and the vehicle in front.

That two-second rule is based on the driver’s “thinking distance,” or how quickly the driver must respond to a change in speed in the vehicle in front, and the “braking distance,” which is how quickly the vehicle can reduce its speed. Trucks tested in trials by automakers like Volvo and Scania have driven in platoons with gaps of less than one second between them.

Connected truck platoons can greatly reduce “thinking distance,” if not eliminate it entirely, because the trucks farther back in the convoy can react almost instantly to changes in speed in the leading vehicle. The tighter a platoon, the less fuel is used and the less carbon emitted.

The UK government is proposing that the two-second rule be “relaxed” for vehicles fitted with platooning systems. “There is an opportunity to reduce the separation distance required between these vehicles, and hence to maximise the efficiency gains through reduced aerodynamic drag,” according to the government’s Centre for Connected and Autonomous Vehicles, which prepared the proposal.

There are a raft of other regulatory changes that the UK government wants to make. Along with platooning, it wants to adapt the rules to allow other technologies that are nearly commercially available, like automated remote-control parking, where the driver has exited the car; and motorway assistance, where drivers can temporarily take their hands off the wheel. It’s also laying the foundation for changes in insurance rules for automated driving, proposing a system where automakers are likely to share the risk with insurers.

The government is seeking public feedback on its proposals until Sept 9. It won’t be making changes to the laws immediately; if this round of feedback goes well, it’ll publish more detailed plans and seek public comments on that sometime next year.

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