The most important piece is by Charles Montgomery, who travels along with Lon Laclaire, the City’s Strategic Transportation Manager, and learns some lessons. Like this one:
In 1968, the German mathematician, Dietrich Braess, was modelling the response of traffic to different road networks. Braess assumed that drivers keep adjusting their trips until they find the quickest commute possible. This is one of the premises of EMME/2, the computer program used to predict traffic flows in every big city around the world. The EMME/2 models assume that, like water molecules in braided streams, cars will distribute themselves until all roads are pretty much flowing equally. This is why the Alex Fraser Bridge was jammed within a few months of opening. It’s also why your shortcut to work never stays a shortcut for long.
Braess discovered a curious wrinkle in the traffic universe. His math showed that adding new capacity to an existing network of roads can actually lengthen peoples’ commute time. This fact is fueled by human selfishness: We all try to choose the fastest route home. But when ten thousand of us make that same choice in isolation, we all just might arrive home later.
LaClaire heard about Braess’ Paradox from a visiting traffic scholar in a Wall Centre conference room back in 2000. He remembers the equation, and the epiphany it brought. His blue eyes twinkle as he recalls the moment he raised his hand.
“I said, ‘Hey, maybe these paradoxes, these problem roads, already exist in our city. If they did, we’d just need to take them out to improve the flow!’ I thought it was a brilliant idea. I mean, these problem roads must be out there.”
In the engineering world, it has long been heresy to suggest that less concrete and asphalt might be preferable to more. LaClaire had crossed the line. “The guy looked at me like I was a freak. He laughed, like I was joking, and then he just went on teaching.”
LaClaire furrows his brow as we cruise through another amber. “But I was right.”