Unjamming traffic congestion: Computer-based systems can speed traffic, increase safety, and improve gasoline mileage

“If we can land a man on the moon, then we should be able to find a green light on our roads when we need it” may be the way a frustrated driver caught in a traffic tieup sees things. But to traffic engineers, the sentiment reflects widely held myths concerning what even the latest equipment — computer-based traffic-control systems — can reasonably do and what it cannot.