DRIVERS NEED NOT APPLY: TerraMax (opposite) is a self-driving, 7-ton, 6-wheel-drive, all-terrain vehicle built by Oshkosh Truck Corporation. The XAV-250 (#15) is a highly modified Ford F-250. Cornell University’s entry, Skynet (#26), finished the course in a bit over 6 hours.

Several rounds of tough competition eliminated most of the contestants prior to the competition’s final day. Just 11 vehicles out of the 36 semifinalists were still in the hunt. Those remaining were given three missions to complete. Moments before race time, the teams were provided with details of their secret missions, the information provided as a computer file on a USB jump drive handed to each team’s leader. Each mission was different, requiring the vehicle to negotiate through the sometimes heavy DARPAtown traffic. To be eligible to win, a vehicle had to successfully complete all three missions in less than six hours.

At first look, designing a self-driving car may seem impossible. But really, “it’s just an extension of present technology,” says Michael Darms, an engineer with the Tartan Racing team. “Cruise control, which is a first step, has been around for decades.”

Darms lists numerous examples of existing cars that handle more and more of the tasks of driving. Many luxury cars have smart cruise control that automatically maintains a safe distance from the cars ahead. Further, some have anticipatory braking systems that use radar to anticipate a crash and pre-charge the brakes for a faster stop.

The vehicles at Urban Challenge must go beyond simply removing the driver’s foot. They must remove the driver’s brain.

But the vehicles at Urban Challenge must go beyond simply removing the driver’s foot. They must remove the driver’s brain. Doing so requires a great deal of technology. In use here are radar, LIDAR (light detection and ranging), gyroscopes, and machine vision sensors, all of which paint an incredibly detailed digital image of the area surrounding the vehicle for use by the onboard computer. Control schemes include sophisticated “fly-by-wire” systems that turn the car’s wheels and apply its brakes. And the GPS systems used are incredibly accurate, telling the car where it’s located to within a few centimeters.

The teams at the Urban Challenge range from huge groups from corporations and universities with millions of dollars in funding behind them, to groups of five or six tinkerers who modified their personal cars. As one might expect, the greater the resources, the better the self-driving cars perform, for money does matter. But all of the robot cars here, even the low-budget ones, perform admirably. Here are some typical Urban Challenge entries, ranging from the simplest to the most elaborate.

SIMPLEST: ODY-ERA

While other entrants have paint jobs proclaiming Ford, Caterpillar, and Google as sponsors, Ody-Era’s decals include Papa’s Italian Bistro and Mac’s Fabrication Shop. Ody-Era, a 2008 Mercury Mariner from Kokomo, Ind., may not be the most sophisticated, but the fact is, its makers legitimately qualified to compete at DARPAtown against teams a thousand times larger and richer. They showed that a few makers working in a home garage can still attempt great things.

“We’ve spent less than $20,000 in total on our vehicle,” says Rick Bletsis, the driving force behind this self-driving car. Yet Ody-Era made it through several levels of competition in order to compete in the Urban Challenge at DARPAtown.

Unlike most other competitors, Ody-Era relies mostly on machine vision to guide itself through the course. “We use inexpensive, off-the-shelf digital

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