When the Freightliner Inspiration truck leaves its parking place near the Las Vegas Speedway, Christian Urban, the driver, starts off as on any other trip, moving the steering wheel and operating the pedals.
But when the vast truck is on the public road, a message on the dashboard tells Mr Urban that a program called "Highway Pilot" is ready to take over. After pushing a button on the steering wheel, the truck steers, accelerates and brakes without the intervention of Mr Urban, an engineer at Freightliner's headquarters.
Germany's Daimler, Freightliner's parent, has hailed the Inspiration - which was granted permission on Tuesday to operate on Nevada's roads - as the first autonomous truck licensed to operate on public streets.
But while the state's decision is significant, the step looks more evolutionary than revolutionary. Daimler portrays the Inspiration as the next step from vehicles that warn drivers when they are leaving their lane and control braking if too close to the vehicle in front.
Wolfgang Bernhard, chief executive of Daimler's bus and truck division, says regulatory and technical challenges mean it is likely to be five years before the Inspiration is made available to commercial truckers.
"The biggest obstacle that we see is the regulatory framework," Mr Bernhard says.
Jude Hurin, a senior manager at Nevada's department of motor vehicles involved in approving the Inspiration, says the challenges differ from those for safety-critical innovations such as cruise control.
"We believe that this is a milestone event," Mr Hurin says. "The governments - state as well as national and international - have to reach out of the old way of thinking and we need to partner with the industry."
The core argument for pressing ahead with autonomous driving is that it will cut the death toll on the US's roads. The majority of the 32,719 people killed in road crashes in the US in 2013 - the most recent year for which full figures are available - died as a result of driver negligence.
<
The tabular content relating to this article is not available to view. Apologies in advance for the inconvenience caused.
> In other transport fields such as air travel and railways, computers have shown themselves better at maintaining the concentration and patience with which human drivers struggle over long-haul and routine journeys. The Inspiration is intended to take over such routine driving from human truckers."The system never gets tired," Mr Bernhard says. "It never gets distracted. It's always at 100 per cent."
However, the nature of the deaths in autonomous vehicle crashes is likely to be different. A higher proportion of such crashes could raise questions about how the vehicle, its sensors and software handled an emergency than at present.
US legislators and regulators, who take a more relaxed view than European governments of the speed and driver error that cause most crashes, have traditionally been harsher on crashes resulting from vehicle faults, such as General Motors' botched ignition switch recall.
Mr Bernhard wants a US-wide certification system partly to ensure manufacturers do not find themselves liable for future crashes that technology could have avoided. Regulators should lay out, for example, what kind of obstacles a system should be able to spot and which street markings it should recognise.
"All of these questions have to be put down in a number of criteria that need to be fulfilled before we let this system loose on public roads," Mr Bernhard says.
Mr Hurin argues that autonomous driving's potential benefits are so substantial that the regulatory system should be rethought.
"Safety is a foundation," he says. "But we have to make sure that our partnership with industry is realistic and safe and innovative and doesn't get in the way of making this programme a success."
In a Daimler video, a series of senior executives at big US trucking companies - including Swift Transportation and Con-Way - extol the benefits of autonomous trucks. As well as safety, they mention the potential for "platoons" of autonomous trucks driving in convoy to save fuel.
<>Yet Daimler accepts that its technology has yet to match the flexibility of humans, whose brains Martin Daum, chief executive of Daimler Trucks North America, calls "the best computer money can't buy". As such, Daimler is uninterested in pursuing the driver-free technology that Google and others are pursuing.
An incident during the drive in the Inspiration makes the point. As Mr Urban watches the vehicle drive down Interstate 15 near Las Vegas, powerful desert crosswinds are battering the truck. The battering grows worse as two other trucks pass and the Inspiration's lane-keeping system fails to keep the vehicle on the intended path.
The system recognises its limits, flashes a red alarm on the dashboard and pleads with Mr Urban, "Take control".
© The Financial Times Limited 2015. All rights reserved.
FT and Financial Times are trademarks of the Financial Times Ltd.
Not to be redistributed, copied or modified in any way.
Euro2day.gr is solely responsible for providing this translation and the Financial Times Limited does not accept any liability for the accuracy or quality of the translation