From the very beginning of The Speculist, the flying car has been a favorite topic. Our fascination has a lot to do with the esthetics of the future. When we think about what the future should look like, few things can compete with the image of a sky darkened with cars.

There will be more crucial, less flashy developments – strong AI, life extension, cheap and plentiful power. Even within the field of transportation, there is another development that could be more important than getting vehicles off the ground – autonomous transportation.

The Stanford Racing Team's autonomous car, Junior, passed a complex driving test Thursday [a week ago today], making it one of the few robots in the world able to deal with the complexities of city traffic. Well, maybe small town traffic. "It drives like my grandma," exclaimed one bystander, as Junior cautiously pulled up to an intersection, turned on its blinker, waited ten seconds, and then pulled cautiously and jerkily around the curve.

Pathetic for a human -- but pretty damn impressive for a completely self-contained, autonomous robot.

Give Junior a break. I'm sure that safety is the primary software consideration. We human drivers can learn how to judge risk – remaining acceptably safe while becoming acceptably speedy. But this takes time and our real-world results are hardly perfect. I suspect that Junior-inspired systems will improve faster than anticipated.

The computer hardware involved is powerful, but not exotic. Junior is powered by two rack-mounted Intel servers - one with an Intel Core2 Quad chip, the other with an Intel Core2 Duo chip.

Junior's "eyes" are a little less off-the-shelf:

The sensors include a roof-mounted laser rangefinding system that spins 15 times per second to build up a 360-degree view of its surroundings, out to a distance of about 65 meters. Additional lasers on the car's corners give Junior detailed data about nearer objects, such as curbs. Positioning data comes from a module supplied by Applanix, which uses three accelerometers and three gyroscopes, plus data from wheel sensors, to augment the car's GPS receiver.

Stanford has been using Volkswagens for these contests because modern VW's have fully electronic control systems. It's relatively easy to wire in those Intel servers.

The Stanford engineers just patch a Category 5 cable into the [VW control] system, and their computer drives the car by passing UDP data packets to it.

Autonomous travel is a necessary step toward flying cars. Driving on the ground has proven to be quite a challenge for the public. Adding a third dimension will only increase the complexity and danger. Much of this complexity will have to be managed by computers.

Back to the Future II imagined highways in the sky. I doubt seriously that we'll ever see floating signposts and road markers. There seems little point in going to the trouble to do this in reality when it could be done digitally even with today's technology. But the highway idea is a good one. It essentially would divide the sky into Interstate highways complete with virtual exit ramps to the ground. These would be no harder for drivers to navigate than an Interstate on the ground.

But computer systems would need to be involved to control altitude and insert the virtual signposts and road markers in the heads-up display. If computers are already doing that much, they would be capable of doing all the driving.

Much of the freedom that we associate with flying cars can be accomplished by autonomous vehicles on the ground. There's little physical effort involved with driving, but we feel tired after a long drive – particularly in heavy traffic or bad weather. Driving a car requires focused attention and mental effort. If we could be relieved of that effort, a car ride isn't bad. Time in the car could be productive work time or we could relax with television, music, or the Internet. Most of us could reclaim at least an hour a day.

Although autonomous driving is a prerequisite to flying cars, future Juniors could actually push more of our travel to the ground. If I didn't have to actually man-the-wheel for twenty hours, a drive to the Rockies would be no big deal for me. I'd buy one of these...

...and kick back while it drives me all around the country (it would, of course, be powered by a plug-in hybrid biodiesel engine).

Except for very long trips many of us will find autonomous vehicles preferable to the hassles of commercial flying.