DENVER (AP) — Colorado's transportation agency began using a driverless truck on Friday that is designed to protect highway work crews from oncoming traffic.

The truck is officially known as an Autonomous Impact Protection Vehicle, but it is not really autonomous like the self-driving cars being tested around the country. Instead, the truck is electronically controlled by a driver in another truck ahead of it.

If the protection vehicle loses its electronic "tether" to the lead vehicle, it is programmed to pull over and stop.

Like other trucks that follow highway crews and display messages or arrows telling drivers to shift lanes, it has a large cushion to absorb the impact of vehicles that may crash into it. In Colorado, that happens an average of six times a year, making driving such vehicles one of the most dangerous highway jobs, state officials say.

"It just didn't make any sense to me to have a human being in a truck designed to be hit," Shailen Bhatt, executive director of the Colorado Department of Transportation, said in an interview Friday.

With a growing population and billions in unfunded road projects, Colorado has embraced technology to help it make the best use of the roads it already has. But while the state hopes to eventually add more driverless escort trucks, freeing up workers for other duties, Bhatt said safety, not saving money, is the main motivation.

Bhatt said he believed that Colorado is the first place to use the driverless trucks for road work. His department says it has been tested in Florida but not deployed. The Federal Highway Administration said it was not aware of any other such trucks in use.

Officials used the vehicle Friday to follow a crew striping a road in Fort Collins, home to Colorado State University. It will be used more widely in the fall after further testing and consultation with the Colorado State Patrol, Bhatt said. Eventually, it may be used on all sorts of road projects, including snow plowing.

The truck was built by Pennsylvania-based Royal Truck & Equipment using technology adapted by another firm, Kratos Defense and Security Solutions, from the military. The transportation department said another company, Colas UK, is testing the technology for use in the United Kingdom and also shared its lessons.

A representative with California-based Consumer Watchdog, a nonprofit group skeptical of driverless technology, said Colorado's experiment has the potential to save lives.

John Simpson said the technology sounds like that being tested for rows of trucks that follow a lead vehicle, allowing them to save fuel by drafting off one another. But he said billing it as autonomous misrepresents what truly autonomous vehicles can do, such as navigate their own routes and turn.

"This is a very novel and probably very good application of the technology once it's fail-safe and people see it for it is," Simpson said.

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This story has been corrected to show John Simpson said "see it for what is," not "sell it for what it is."