Gridlock is a problem of density--too many cars, not enough roadway--so proposed solutions have taken two forms: Reduce the number of cars (by carpooling or public transportation), or build new roads. These solutions have proved unfeasible or expensive and have provided little relief. Now technology offers us a third option: Make our cars into trains. By joining into a virtual platoon--linked to one another by wireless rather than physical connections--we can increase the density of cars on the road without slowing them down. So-called pod cars could charge through cityscapes with no assistance from the humans inside, who would then be free to read the paper or watch TV. Elements of this technology are on the roads today. Automatic cruise control uses radar to gauge the distance to the car in front of you and to slow down if you're approaching too quickly. The Japanese versions
of certain Nissans can be ordered with a "lane-keep" system, which uses digital cameras to monitor lane markers and ensure that you stay in your own. Combine these systems for basic autopilot with steering, gas and brake controls. Then add car-to-car communications, and you can link up to 10 vehicles into a fast, dense chain acting as one. The technology needed to make pod cars thoroughly safe is still a decade off; until then, ideas borrowed from
them will seep into modern cars and, inevitably, into the way we drive--or don't.