Are you ready to share the road with a self-piloting big rig?

Nevada issued the first license to an autonomous big rig, Daimler's Freightliner Inspiration. Can we really trust a computer to operate a huge truck? 

Drive on a Nevada highway, and you might see something you've never seen before outside of the movies: A giant robot truck.

At a ceremony at the Hoover Dam on Tuesday, Nevada governor Brian Sandoval granted a license to Daimler's Freightliner Inspiration big rig truck, officially making it, in Daimler's words, "the first licensed autonomous driving truck in the US"

Unlike, say, Optimus Prime, this truck is not entirely autonomous. Instead, Daimler calls it "collaborative vehicle system," in which a licensed truck driver plays a key role. 

Here's how it works, according to a Daimler press release:

As soon as the Freightliner Inspiration Truck is safely on the highway, the driver can activate the Highway Pilot system. The driver receives a visual prompt in the instrument cluster to activate the "Highway Pilot." The vehicle switches to autonomous mode and adapts to the speed of traffic. The driver receives a confirmation message in the instrument cluster, "Highway Pilot active."

The Highway Pilot system uses a complex stereo camera and radar systems with lane-keeping and collision-prevention functions. It regulates the speed, applies the brakes and steers. This combination of systems creates an autonomous vehicle that can operate safely under a wide range of driving conditions – the truck automatically complies with posted speed limits, regu­lates the distance from the vehicle ahead or uses the stop-and-go function during rush hour.

The truck won't pass or change lanes on its own, and the driver will need to take control upon leaving the highway. Additionally, if the truck's software encounters something it cannot handle, such as bad weather or road construction, it will alert the driver to take the wheel.

"The autonomous vehicle technology we are showcasing in the Freightliner Inspiration Truck will help reduce accidents, improve fuel consumption, cut highway congestion, and safeguard the environment," said Daimler's Wolfgang Bernhard, who took the truck's first drive, with Gov. Sandoval in the passenger seat.

According to a 2014 report from the RAND Corporation, the National Highway Traffic Safety Administration suggests five gradations of vehicle autonomy: 

• Level 0: The human driver is in complete control of all functions of the car.

• Level 1: One function is automated.

• Level 2: More than one function is automated at the same time (e.g., steering and acceleration), but the driver must remain constantly attentive.

• Level 3: The driving functions are sufficiently automated that the driver can safely engage in other activities.

• Level 4: The car can drive itself without a human driver. 

Daimler classifies its new big rig as a Level 3 autonomous vehicle: If something goes wrong, there is a human driver to fall back on.

There are some Level 2 or Level 3 vehicles on the market already. Mercedes-Benz and Infiniti already include lane-keeping features. Tesla is planning for next year’s Model S sedan to be able to take over some highway driving, and Cadillac will introduce a similar “Super Cruise” feature, according to published reports. Subaru and Volvo both have automated collision warning features.

But how much safety does the human element add? Most experts agree that humans tend to overrate their ability to drive safely. One notable study 1980 found that 88 percent of US drivers rated themselves as safer-than-average, compared with 77 percent of Swedes.

“It’s always the other person who’s the bad driver,” says C. Gregory Russell who’s been an accident investigator for the Trident Engineering of Annapolis, Maryland, for 25 years, in an interview. “Trust me, I’ve seen people do some really screwy things and manage to wreck things and do stuff that you wouldn’t believe they could do.”

"It just seems to be human nature,” he says.

John Ulczycki, vice president of the National Safety Council in Itasca, Illinois, seems to share Mr. Russell's disenchantment with people's driving skills. He has ridden in a (Level 4) Google car, and says  in an interview, “it is by far the safest driver I have ever ridden with.”

“Ninety percent of the crashes today are caused by human error,” Mr. Ulczycki says. “Ninety percent of crashes taking place are caused by humans making mistakes."

According to the Centers for Disease Control, 33,804 people died in motor vehicle crashes in the United States last year.

“I would trust that equipment [in driverless cars] more than I trust humans because I see how humans drive every day,” Ulczycki adds. “We know how humans drive and cars that are all driving in a safe manner and have a level of predictability of how the other vehicles are going to behave will result in much safer roadways and probably more efficient roadways.”

“We’ll probably get where we’re going more efficiently, more safely, because the human component that causes much of the disruption on our streets and freeways will be decreased, diminished and disappear entirely.”

Russell agrees that a move to fully-automated driving roadway systems “will be for the better until somebody has one accident where a system has failed and then everybody will be marching around saying ‘look how horrible these are, look how unsafe they are.’ They’ll look at the one, versus how many that would save.”