New York City Embraces a Bold New Traffic Theory

As the mayor of New York City, Michael Bloomberg usually takes the subway to work. When he travels by car, a police escort zips him through rush-hour congestion. But for a man who himself spends little time mired in Manhattan's inch-along, horn-chorused gridlock, Bloomberg seems oddly obsessed by traffic—and as a committed environmentalist, he aims to do something to reduce it. "The midtown traffic mess is one of those problems everyone always talks about," he said last week. "Well, we're not just going to sit back—we're going to try to do something about it." His plan: to permanently bar traffic from large swaths of Broadway.

It's the boldest example to date of an American city embracing the emerging—and controversial—theories of traffic science. While it's tempting to see the logjams on Los Angeles's 405 or Chicago's Dan Ryan Expressway as inevitable byproducts of our car-based culture, writer Tom Vanderbilt observes in "Traffic: Why We Drive the Way We Do" that congestion has plagued humans even as they migrated from foot to oxcart to bicycle. But a new generation of theorists is using economics to try to speed things up. For Bloomberg, who's seeking a third term this November, experimenting with these theories carries risks. Early reactions have been favorable, with a few notable exceptions; one columnist wrote that the Crossroads of the World is "soon to be known as the Traffic-Choked, Tourist-Loving, New Yorker–Hating, Immovable Crosswalk."

When it comes to New York traffic, Broadway has long been identified as a key culprit. In 1811, urban planners laid out Manhattan's grid of north-south avenues met by east-west streets, an efficient system of right angles. But those mapmakers left Broadway slicing diagonally through the city, and it's caused havoc ever since. "Every time Broadway cuts through the grid, it delays traffic," says Janette Sadik-Khan, New York's transportation commissioner. It's especially bad at Times Square, where drivers on Broadway and Seventh Avenue meet heavy crosstown traffic—along with 356,000 daily pedestrians.

In general terms, traffic is caused by too much demand (from vehicles) meeting too little supply (roads). One solution is to increase supply by building more roads. But that's expensive, and demand from drivers tends to quickly overwhelm the new supply; today engineers acknowledge that building new roads usually makes traffic worse. Instead, economists have suggested reducing demand by raising the costs of driving in congested areas. The best-known example is the "congestion pricing" plan London implemented in 2003. Drivers now pay about $11 a day to drive in the central city. According to one study, the program has reduced traffic by 16 percent.

In 2007 Bloomberg proposed a congestion-pricing plan for New York, but last year state legislators rejected it as an elitist move. In response, Bloomberg began tinkering with the city's roads in ways that required no legislative blessing. He banned vehicles from Park Avenue for three Saturdays in August 2008. He closed two lanes of traffic on Broadway below 42nd Street. "Bloomberg is taking the position that as long as it's within the two curbs, it's [city] property and he can decide how to use it," says Sam Schwartz, the city's former traffic commissioner.

These pilot projects fit in with a larger counterintuitive theory that's gaining traction with urban-planning wonks: that closing roads can reduce congestion. During the 1990s, a British transit engineer named Stephen Atkins read about how San Francisco congestion decreased, rather than increased, after an earthquake knocked out a key freeway. He observed the same phenomenon in other cities that closed roads, too. "In a lot of places, the traffic was not just displaced—a lot of it disappeared," he says. In a 1998 study he commissioned, researchers studied 60 cases of road reductions and found that when roads were closed, drivers took steps to avoid the area. In economic terms, closing roads raises the perceived costs of the trip (because drivers anticipate hassles), reducing demand.

Green growth advocates, who have gained much influence in Bloomberg's administration, originally thought about closing all of Broadway below 59th Street. That was deemed too radical, so the plan unveiled last week closes only seven key blocks of the Great White Way. Last month Sadik-Khan unfurled an enormous map and pointed to the horrible intersection outside Macy's, at 34th Street. Under the new plan, Broadway is closed off one block above and below the intersection, creating adjacent pedestrian malls and allowing Sixth Avenue and 34th Street to meet cleanly. A similar five-block no-drive-zone will border Times Square; together they should reduce congestion by 37 percent on Sixth Avenue, 17 percent on Seventh and some 20 percent on Ninth.

Manhattan is a one-of-a-kind city—an island with its streets in a grid, minority car ownership and a superb transit system. But if the Broadway shutdown works, the scheme could spread to other cities, too. San Francisco last week announced it would study barring cars from a portion of Market Street in order to get bicycles, buses and pedestrians moving more quickly. "I think that 21st-century cities are looking at their streets differently," Sadik-Khan says. "They're saying, 'We need a fresh look at how we're getting people around, and it's more than just pushing as many cars into a city as possible'."

For Bloomberg, 67, a politician who retains an entrepreneur's love of big ideas and risk-taking, there's no doubt it's a plan that makes sense. Based on current polls, he seems likely to win a third term, so it's time to think about his legacy. Ultimately he'd like to leave New York a greener, more livable city—and one with a lot less honking. That's a wonderful vision indeed.