A robotic Humvee has managed to drive itself for seven hours without crashing on a race course in the US.
Sandstorm completed the trial race in seven hours
The robotic vehicle built by Red Team Robot Racing from Carnegie Mellon University covered 200 miles (322 kilometres) during the trial.
The test was part of preparations for a robot vehicles race across the Mojave desert organised by the US Defence Advanced Research Projects Agency.
The race, called the Grand Challenge, is due to be held on 8 October.
The aim of the competition is to encourage research into robot vehicles. To win a cash prize of $2m (£1.13m), the autonomous racers must make their own way across the desert course within a specified time limit.
In the first Grand Challenge held last year, none of the robot cars taking part made it to the finishing line.
Sandstorm, from Carnegie Mellon University, made it the furthest distance down the course and the team are now looking at doing better this time round.
In an endurance test of the vehicle's computers, sensors and mechanical systems, Sandstorm drove 131 laps on a race course near Pittsburgh, covering the distance in seven hours.
The adapted hummer averaged 28mph (45kph) and hit a top speed of 36mph (57kph).
"That doesn't sound like a big deal for a human-driven car, but it is a very big deal for the pioneering of computer-driven vehicles," said Red Team leader, robotics professor William "Red" Whittaker.
"That distance, speed and duration are unprecedented for a completely autonomous machine. However, this machine and 19 others will face far more difficult conditions in the race across the Mojave Desert.
"Sandstorm ran a quick pace on this track, but the Mojave will not be so easy or forgiving."
Sandstorm and its sister machine, the Hummer H1ighlander are among the 40 vehicles taking part in qualifying rounds for the Grand Challenge between 26 September and 6 October.
Out of these, 20 will make it through to compete in the desert marathon for the cash prize.