Robots on the road

Robots on the road - how close is our driverless future?

It was on the motorway near Phoenix, Arizona, that I realised fully driverless cars might be quite a distant dream. And that was because our Google Waymo robo-taxi seemed incapable of leaving that motorway.

We were in Arizona to record about the progress towards creating autonomous vehicles that would make our roads safer and replace human drivers with robots.

Google leads this race at the moment and for the past six months has been offering a robo-taxi service, Waymo One, to a select few early adopters in and around the Phoenix suburb of Chandler.

Our first ride with Waymo took us through the quiet suburban streets, where traffic is sparse and drivers well mannered.

Here, the minivan, fitted out with a battery of sensors and high-definition cameras, performed very impressively, handling slightly tricky left turns, spotting other road users and slowing down as it passed a school.

While a Google engineer sat behind the wheel, she never intervened and soon we relaxed and forgot that we were effectively being driven by a robot.

Then, we hitched a ride with Shawn Metz, one of a few hundred locals selected as customers of Waymo One.

He told us he and his wife used the service for their weekly shop, nights out and in places with limited parking.

"We're hoping to go from a two-vehicle to a one-vehicle household eventually and optimistic this technology might get us there," he said.

But as we headed along the motorway on the 20-minute ride to his office, things began to go wrong.

As we approached our exit, there was a solid line of traffic to our right.

An assertive human driver would probably have squeezed over and made it to the exit lane - but the robot, which cannot exceed the speed limit, was more cautious.

The car missed that exit and the next one before finally leaving the motorway.

And when we were back on the suburban streets, it appeared to freeze at a junction where it needed to turn left across traffic - after a while, the engineer behind the wheel had to take over and complete the turn.

Mr Metz told us that in his experience this was a very rare occurrence.

Slow progress

Nevertheless, it served as an illustration that the Waymo autonomous driving technology, widely thought to be ahead of its competitors, still needs to be refined.

It is understandable, however, that the system is programmed to be ultra-cautious.

After all, just a few miles away, another self-driving car killed a pedestrian in an accident in March 2018, which shook confidence in autonomous technology.

The car belonged to Uber, one of Waymo's big rivals, and it ploughed into a woman pushing a bike across a road near Arizona State University.

The safety driver had been watching a video on her phone at the moment of impact.

The ideal road and weather conditions coupled with welcoming local officials have made the Phoenix area one of the world's leading locations for testing autonomous vehicles.