They've unleashed their new robotic beasts as part of the Robotic Autonomy in Complex Environments with Resiliency (RACER) programme and it is those eerie green peepers on the tanks that have everyone talking.

These RACER Heavy Platforms (RHP) monsters tip the scales at 12 tonnes and stretching 20 feet. They're kitted out with the Textron M5 system, which is already a hit with the Yanks' driverless army drivers. And they're here to show the smaller RACER Fleet Vehicles (RFVs) how it's done, with the little 'uns weighing a mere 2 tonnes and measuring 11 feet.

DARPA had boffins from the University of Washington and NASA's Jet Propulsion Laboratory put these metal giants through their paces at some hush-hush military training grounds in Texas last year. But they've only just decided to spill the beans about it now.

A YouTube video shows these behemoths barrelling through off-road terrain like nobody's business.

So, what's the story with those green orbs? A DARPA spokesperson told Gizmodo, "....it’s just an indicator light to show the vehicle's status. Green = it’s on and in autonomy mode." Well, that's a relief. Here we were, thinking it had its evil personality and was about to start a fight.

Of course, it is not so sensible to have these things running at night where the green lights are like sticking a big target on it, but we are sure they are optional.

DARPA's also added another video featuring the nippier RFV models doing their thing in autonomous mode. The crew behind the wheel—well, not literally, since these bad boys drive themselves—were newbies to the game, making the whole experiment as raw and real as it gets. The aim? To see how these robotic road warriors handle terrain as foreign to them as a decent cuppa is to an American.

The press release from DARPA is a proper mouthful: “Using fully unoccupied RFVs, RACER demonstrated autonomous movement within a 15 square mile terrain area including highly diverse ground vegetation cover, trees, bushes, rocks, slopes, obstructed ditches, and creek crossings typical of the varied, complex Texas terrain familiar to armoured manoeuvre.”

DARPA's been fiddling with driverless vehicles since '83, and they have come a long way. Back in the day, some snow would throw their Autonomous Land Vehicle into a right tizzy. But now? Pfft, a bit of rough weather's got nothing on these modern marvels.

Stuart Young, the big cheese of the RACER programme,, said, “Having two radically different types of vehicles helps us advance towards RACER’s goal of platform-agnostic autonomy in complex, mission-relevant off-road environments that are significantly more unpredictable than on-road conditions.”