Look closely. That truck driver has both hands on his iPad.

Freightliner has been given a license to test out its autonomously driving tractor-trailer truck in the state of Nevada. The big-rig manufacturer already has such a truck in operation and will now begin test driving it on public highways there.

There will always be a licensed truck driver in the driver's seat but the Frieightliner Inspiration is designed and equipped to drive itself on limited access interstates. There are currently two of the trucks. A human driver will take full control when the truck is in city and suburban driving situations. Nevada is one of a few states that has legislation specifically allowing for the licensing of self-driving vehicles.

The Freightliner truck will stay in its lane and avoid hitting cars ahead with no driver input. Radar sensors and cameras will watch lane lines and surrounding traffic. Freightliner is owned by Daimler AG (DDAIY), which also makes Mercedes-Benz luxury cars. Mercedes has also been testing self-driving cars.

Trucks like this could reduce driver fatigue, according to Freightliner executives, and allow drivers to be more productive. While the truck is going down the highway, the driver could safely attend to paperwork or plan the next trip, for instance.

Automated trucks could also save fuel by driving in "platoons." In this scenario, automated trucks, communicating with one another electronically, could drive in a tightly packed line behind a lead truck. This would have huge aerodynamic benefits because only the truck in front would have to push through a lot of air. Each following truck would ride in a sort of bubble created by the truck in front of it.

Autonomous driving technology will, at some point, find its place in the in the trucking industry, said Wolfgang Bernhard, who heads Daimler's commercial truck operations.

"We don't believe that everyone is going to jump on immediately," he said. "It's a process."

Getting experimental trucks out on real roads is a step in that process.

"From an industry standpoint, it's going to be a question of cost versus benefit," said Ted Scott, director of engineering for the American Trucking Association, a group that represents the trucking industry. This technology is going to add to the cost of the rig which will still need a paid professional driver at the wheel.

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Not everyone is sold on the idea of self-driving semis. Scott Grenerth is director of regulatory affairs for the Owner Operator Independent Drivers Association (OOIDA), a group that represents independent truckers. He spend 13 years driving big rigs, he said, and he'd be very nervous handing control of an 80,000 pound vehicle to a bunch of cameras and sensors.

Given a big trucks' long stopping distances and limited maneuverability, driving one requires the ability to correctly predict what's going to happen far out ahead. That requires foresight and intuition that are difficult to program into computers.

These trucks are going to have to pass through some tough legal checkpoints in coming years, Bernhard said. Right now, it's not clear, in the event of a crash, who would be responsible, the truck or the driver? Also, interstate trucks, by definition, travel across multiple states. This technology won't be practical if rules about its use vary from one state to the next.

In many states, for instance, using an iPad in the driver's seat would be illegal even if the truck could drive itself, said Bryant Walker Smith, a University of South Carolina law professor who has written about autonomous vehicles. Also, in New York, the law specifically states that the driver must have a hand on the steering wheel at all times, he said.

Self-driving trucks are coming, though, Bernhard said, and probably sooner than many people think.

"Long before autonomous vehicles are cruising the suburbs," he said, "you will have autonomous trucks on the highway."