UK roads pose unique challenges for government’s driverless car ambitions

The UK government wants self-driving vehicles on public roads by next year, backed by the Automated Vehicles Act 2024 and billion-dollar bets from firms such as Wayve and Uber.

“The future of transport is arriving. Self-driving cars could bring jobs, investment and the opportunity for the UK to be among the world leaders in new technology,” said transport secretary Heidi Alexander earlier this summer, declaring it was full speed ahead for self-driving trials in the UK.

But while there is serious ambition to put self-driving taxis and buses on the tarmac, making it happen might be more difficult than the government thinks.

Some US and Chinese cities already have bustling fleets of autonomous vehicles ferrying passengers back and forth, and an increasing number of cities and other countries – particularly in the Middle East – are signing deals to bring similar services there. The UK’s roads are a very different environment, however.

“The technology is only going to make sense in some particular contexts, even though it’s often talked about in this sort of way – that the technology will ‘do everything and go everywhere that a human can go’,” says Jack Stilgoe, an expert in autonomous vehicles (AVs) at University College London. It’s one of the industry’s biggest secrets, says Stilgoe, that AV technology isn’t equally applicable in all environments.

There are broadly two forms of autonomous vehicle technology. One, developed and deployed by the likes of Waymo, involves using a combination of sensors, including lidar, radar and cameras, together with highly detailed 3D maps to perceive and navigate the environment.

The other, which is being championed by Tesla, tries to take a shortcut when it comes to the number of sensors. It relies on cameras and neural networks, omitting lidar and radar in an effort to achieve autonomy through a vision-only approach.

One of the biggest challenges that any UK AV trial would face is that the country’s winding and weather-beaten road network exposes stubborn technical, regulatory and social hurdles.

Potholes and erosion of lane markings can wreak havoc on AI-controlled  self-driving vehicle systems that are used to smooth surfaces and clear markings. And with two-thirds of UK drivers noticing faded road markings on their daily drives, according to an RAC survey, keeping in lane will prove tricky.

Self-driving cars can even struggle on roads with clear signs and markings, as viral videos of Tesla Robotaxis in Austin, Texas showed last month, with videos reportedly showing the cars abruptly stopping in the road or appearing to swerve into the wrong lane.

With six potholes per mile on council-controlled roads in the UK, according to the RAC, any self-driving vehicles will be doing a lot of bobbing and weaving.

AV tech has also largely been tested – and had the most success – in US cities, many of which are designed in grid systems. The UK’s high roundabout density, un-marked rural lanes, left-side traffic conventions, smart motorway sensor outages and famously fickle rain and fog could all throw metaphorical spanners into the works.

“London is a particularly hard testing ground for a self-driving vehicle,” explains Stilgoe. “It’s the sometimes called the Sinatra doctrine: ‘If you can make it there, you can make it anywhere.’ If you can deal with London's much more complicated city streets and demonstrate your technology works there, then Phoenix, Arizona looks like a breeze.”

The intermingling of drivers, cyclists and pedestrians on the UK’s road systems – especially when compared to US streets – is also different. Walking and cycling is much rarer in the US, meaning AI systems are less likely to come across it and less likely to know what to do in that situation. The fact that the UK is a densely populated country thanks to its physical limitations also adds to the trickiness.

None of the UK road system’s unique challenges are insurmountable. The success of Wayve, a homegrown start-up trialling autonomous vehicles on the capital’s streets, shows it is possible to get the AV show on the road. And Wayve’s test data will prove useful to any other companies aiming for self-driving operation on UK streets.

It is not impossible to imagine autonomous cars on our roads in the future – but infrastructure and engineering issues mean it might not be as quick as the government would like.