The minivan had a ghostly feel as it crept slowly through the parking lot with no driver behind the wheel, evoking memories of the jealous Plymouth Fury that went off on its own murderous missions in Stephen King’s horror flick “Christine.”

But King wasn’t hanging around the parking lot at Southwest Research Institute on Friday morning when two driverless cars practiced pinpoint turns and other maneuvers for a small audience of reporters. There were just a few brainy robotics engineers, all of them in hot pursuit of a $2 million Defense Department prize that will be awarded in November to a team that best meets the challenge of developing technology that may someday help keep soldiers out of harm’s way.

The military’s goal is to build autonomous vehicles that can deliver military supplies to troops on the front lines, maneuvering urban terrain and the open roads without exposing a driver to enemy fire or land mines. Twenty teams from around the globe are trying to solve the problem, and the San Antonio institute has offered its campus roads and parking lots to teams that need a place to practice. The finals are set for Nov. 3 in Victorville, Calif.

“It’s actually not hard to make a car operate without a driver. The trick is to make it understand where it is and where it is going,” said Chuck Jacobus, manager of Cybernet Inc., one of two teams perfecting their test vehicles here.

“That is 90 percent of the problem,” Jacobus said. “Most of what the car is doing is like a railroad. It is staying on the track.”

The engineers used sophisticated global positioning technology, linking with satellites to tell the van exactly where it is on the globe, with an error margin of less than 4 inches, Jacobus said. The important remainder of the problem, he said, is obstacles that impair the open road: things like pedestrians, curbs, traffic lights and barriers.

For that, the test vehicles are loaded with sensors and analyzers. The Team Berlin van uses a spinning paint-can-sized device on its roof that simultaneously shoots 64 laser beams that feed data to the onboard computer.

The German team earlier built a robotic soccer player, but has found the autonomous auto a more daunting challenge. “You have to watch out for people and other cars,” said engineer Ketill Gunnarsson. “You don’t know what is going to happen.”