Maybe you ran into a platoon of three huge trucks on Thursday traveling way too close to each other on I-66 and Route 28 near Dulles.

The big rigs are part of a transportation experiment and you may soon be seeing many more of them driving roads all over the country.

Developers call it "platooning.” The three trucks were lashed together electronically, allowing them to zip down the road just a few feet and one second behind each other.

"I like it," said truck driver Glenn Eaton. "It's less stuff I've got to do. Just sit back and drive."

Under police escort, and with the help of the Federal Highway Administration, the three big rigs zoomed up Rt. 28 in Centreville with most other drivers probably unaware of what was going on.

“One would definitely feel unsafe driving next to three large ones,” said driver Janae Spencer when she heard about it while filling up with gas. “Especially if two of them aren't manually driven. Yikes!”

The truck platooning system relies on radar, something called cooperative adaptive cruise control, and vehicle to vehicle electronic communication. It's not steering the truck yet. But if another driver cuts to close into the convoy, it will apply the brakes.

“The brakes just..You could really feel it. It kind of gives you a little jar. And it slowed way down,” said Eaton.

Advocates say truck platooning will allow big rigs to drive so close together that it could double existing road capacity.

“Higher density and safety on existing highways as opposed to building bigger highways,” said David Nelson, an engineer with the University of California, Berkeley’s Partners for Advanced Transportation Technology program, which is helping develop the platooning system.

More trucks, less fuel, less pollution supporters say, and more safety.

But...“There is still a lot that needs to be done to educate motorist not to do stupid things when they're driving around trucks,” said Steven Shladover of UC Berkeley.

Federal Highway Administration officials say we may see everyday truck platooning on our roads in as little as a year.

And maybe a few years after that, we may see a driver just in the lead truck, and the trucks behind it might be driverless.