Driving the Ford Fusion at a conservative 20mph, I twisted a red knob on the console to my right and pressed a silver button to engage its self-driving mode. The car leaped forward, instantly surging to 35mph. There was just one problem.

The speed limit here on sleepy River Avenue was 25mph. I nervously pointed this out to the two Uber engineers accompanying me in one of the ride-hailing company’s autonomous cars on Monday. One of them tapped his laptop, and the car slowed to 25mph.

Soon a red light loomed. I kept my foot tensed above the brake pedal, and the Fusion glided to a smooth halt on its own. When the GPS showed it was time to turn on to the 31st Street Bridge, the right-turn signal came on automatically, and the steering wheel slid beneath my hovering hands, turning the car to cross the Allegheny River.

San Francisco's Uber has been testing its self-driving cars here for 18 months after raiding dozens of engineers from Carnegie Mellon University's robotics department. Starting Wednesday, it will put the robot taxis to the ultimate test: Picking up everyday passengers.

The company said it will invite about 1,000 of its most loyal Pittsburgh riders to volunteer for a chance to get free rides in autonomous cars – albeit ones with an engineer at the wheel and another in the navigator's seat – in the nation's first commercial test of a technology that could revolutionise transportation.

Uber’s mission

"Self-driving is core to Uber's mission – reliable transportation everywhere for everyone," said Anthony Levandowski, vice president of engineering at Uber and head of the $68 billion company's autonomous-vehicle initiative. He took on that role last month after Uber paid a reported $680 million for Otto, his San Francisco startup working on self-driving trucks. Levandowski was speaking to a throng of journalists in Pittsburgh. "For me, this is the most important thing computers are going to do in the next 10 years."

Pittsburgh, replete with bridges, tunnels, one-way streets, a complex road grid and brutal weather, presents unique challenges for self-driving cars. "Pittsburgh is the double-black diamond of driving," said Raffi Krikorian, director of Uber's Advanced Technology Centre here.

The project is starting small, with a handful of converted Ford Fusions. By year end, Uber said, it will have 100 self-driving vehicles on the road here, many of them Volvo XC90 SUV hybrids, the fruit of a $300 million partnership with the Swedish carmaker.

The Fusions are off-the-lot cars retrofitted with laser sensors, radar, antennas and cameras that bristle from the roof, bumpers and trunk, and connect to sophisticated software. The Volvos, one of which was on display at Uber’s Pittsburgh Advanced Technology Centre, were designed wheels-up to be autonomous, and that’s apparent from the more streamlined look of their rooftop gear.

"We think of it as: The Fusion is a desktop, the Volvo is a laptop, and next time you're here, you'll see the smartphone," said Eric Meyhofer, ATC engineering head. Uber showcased a fleet of 14 autonomous Ford Fusions and offered reporters 45-minute rides, includng 10 minutes each in the driver's seat. The demonstrations showed that the cars aren't quite ready to operate without a driver. For one thing, they lack sensors to detect sound, so the driver must take over if an ambulance or fire truck sounds its siren, or if a train approaches one of Pittsburgh's numerous railroad crossings that lack a warning signal. While the car slowed instantly when vehicles cut it off, when it encountered a stopped car partially blocking the lane ahead, it sounded a chime signaling that autonomous mode was disengaging. Over the course of an hour, Uber's engineers took over the wheel numerous times, explaining that their goal is to err on the side of safety.

Publicity stunt

Uber's Pittsburgh push has a whiff of publicity stunt. But seeking feedback from regular people and getting them accustomed to robotic cars is part of the challenge for it and others. "You can't get this info any other way; you can't call people on the phone and survey them about autonomous cars, because it would be an abstraction for them," said Karl Iagnemma, co-founder and chief executive of NuTonomy in Cambridge, Massachusetts. Two weeks ago, his 50-person startup beat out Uber with the world's first public test of robot taxis in Singapore. After starting with two cars, it plans to have six vehicles there within the month.

In Uber’s case, an iPad in the backseat displays a welcome message to the rider, and then shows the car heading on its route in a colorful 3-D map generated from the car’s roof-mounted lasers, which continually spin to capture a 360-degree view of its environment.

“The public will play an important role in shaping both social and legal expectations for these vehicles,” said Bryant Walker Smith, a law professor at the University of South Carolina who is affiliated with Stanford’s Centre for Internet and Society. “That’s why companies like Uber should publicly share their safety philosophies – how they define, measure, document, and monitor the reasonable safety of their vehicles now and into the future.”

Uber, known for stormy relationships with regulators, said it would "play ball" and share data upon request with Pittsburgh authorities. Like many states, Pennsylvania has no restrictions on autonomous cars as long as someone is at the wheel.

Regulations

But actually jettisoning the drivers will be quite another matter. “Regulations are something companies won’t have control over, which is scary for companies as they cannot control their own destinies,” said NuTonomy’s Iagnemma. His company picked Singapore for testing because its lawmakers are supportive of the ground-breaking technology.

The National Highway Transportation Safety Administration is expected to release guidelines shortly to help states craft rules for the new technology. The fatal crash in May of a Tesla in autopilot mode is often cited by people who say autonomous cars aren't ready for prime time.

That's a short-sighted view, said Raj Reddy, a Carnegie Mellon professor of computer science who founded its robotics department in 1980. Autonomous cars have the potential to eliminate many auto-accident deaths, which tally more than a million a year worldwide.

“Everyone went to town on the Tesla accident, and no one said, ‘What about the human-caused accidents that result in 100 deaths every day in the US?’” he said. “Politicians could take the lead and say we want to reduce the number of fatal accidents [by allowing autonomous cars]. Initially there may be some accidents along the way, but that is part of the process of building reliable, sustainable systems.”

– New York Times service