The first self-driving vehicle you see may have 18 wheels

Freightliner unveiled its Inspiration self-driving truck during an event at the Hoover Dam Tuesday, May 5, 2015, near Boulder City, Nev. Freightliner unveiled its Inspiration self-driving truck during an event at the Hoover Dam Tuesday, May 5, 2015, near Boulder City, Nev. Photo: Daimler AG - Global Communications Commercial Vehicles, Daimler Trucks North America Photo: Daimler AG - Global Communications Commercial Vehicles, Daimler Trucks North America Image 1 of / 54 Caption Close The first self-driving vehicle you see may have 18 wheels 1 / 54 Back to Gallery

LAS VEGAS (AP) — Although much attention has been paid to autonomous vehicles being developed by Google and traditional car companies, one truck maker believes that automated tractor-trailers will be rolling along highways before self-driving cars are cruising around the suburbs.

On freeways, there are no intersections, no red lights, no pedestrians, making it a far less complex trip, said Wolfgang Bernhard, a management board member of Daimler AG, at a Tuesday event in Las Vegas.

Daimler Trucks North America showed off a self-driving big rig on the road atop Hoover Dam Tuesday night. But the company says the autonomous truck needs more testing before it is ready to hit the highway.

There are many advantages to autonomous big rigs, which use a combination of features that already are available on high-end passenger cars. A computer-controlled truck never gets drowsy. And eventually a fully autonomous rig could cut expensive driver costs for companies.

Still, there likely will always be a human behind the wheel, more as a logistics manager and to take over in an emergency.

Legal and philosophical questions stand in the way, as does perfecting the technology that links radar sensors and cameras to computers that can brake and accelerate the truck and handle any freeway situation.

Legal issues are among the biggest obstacles. Daimler Trucks North America LLC CEO Martin Daum said society might forgive a number of deaths caused by tired truck drivers at the wheel but they would never forgive a single fatal crash blamed on a fully automated big rig.

For now four states, including Nevada, and the District of Columbia, certify testing of autonomous vehicles on public roads as long as a human driver is behind the wheel, and a few others are keen on allowing the tests.

Bernhard said more states need to allow testing of autonomous driving before fleets of self-driving semi-trucks fill U.S. freeways and interstates anytime soon.

"Then it starts to make sense for our customers," Bernhard said, when states that allow it are linked together. "That will be the point when the tipping point is reached."

Bernhard said the company is still far from taking customer orders for the trucks. "We're just getting people inspired," he said.

The truck shown off Tuesday night is called "Inspiration," and Daum said it was a first step, much like landing on the moon.

Taking a line from astronaut Neil Armstrong, Bernhard told the crowd bused to the site from Las Vegas for the news conference that it was about to witness "a short drive for man and a long haul for mankind."

On Wednesday, the company planned test-drives with invited members of the media to show off the automated technology.

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AP Auto Writer Tom Krisher contributed from Detroit.