Smart thinking on transportation

We may have Sam Schwartz to thank that the Williamsburg Bridge, built in 1903, is still carrying a quarter of a million New Yorkers daily between Brooklyn and the Lower East Side in subway cars and automobiles. Since a bike-ped path opened, the bridge has become the most heavily bicycled span in North America, according to People for Bikes. 

Regarding the decision in the mid-1980s, Schwartz writes: "Had we decided to replace the bridge, New York would have had to spend three quarters of a billion dollars on a bridge whose primary effects would have been to destroy existing neighborhoods on both sides of the East River and put even more cars and trucks on Manhattan streets." Schwartz's  was published September 8, 2015. 

The bridge is a testament to why modern traffic engineering needs reform. Now a private consultant, Schwartz was New York City DOT's traffic commissioner and chief engineer when he faced a crisis when a number of important bridges had deteriorated due to lack of regular maintenance. Federal money was required to repair or replace the Williamsburg Bridge, but the feds refused to repair a "substandard" bridge.

What made it substandard? The lane widths average about 9 feet—even narrower at the towers. The standard was—and still is in most cases—12 feet. The bridge would not carry the maximum automobiles at the maximum speed. Schwartz argued that Manhattan did not need more cars, moving faster. The feds' trump card was safety—such narrow, substandard lanes were obviously hazardous, they argued. 

At least it seemed obvious three decades ago. Schwartz mapped every accident on the bridge over a three-year period, proving that the safest parts of the bridge had the narrowest lanes—less than 9 feet. His hypothesis, since proven correct, is that drivers are more careful when lanes are narrow. 

Even today, when multiple studies show that 12-foot lanes are less safe in urban conditions, few traffic engineers question the professional dogma that wide lanes are best. For the last five or six decades, traffic engineers have remade America into an automobile dependent place using that standard. To question it in the 1980s was heretical. 

The bridge was saved and the neighborhoods around the bridge, viewed as slums at the time, now contain some of the most valuable real estate on the planet. This decision went the right way when thousands of others went the other way, coast to coast. The accumulated waste and destruction of those decisions is almost beyond imagination.

This bridge/lane width issue relates to America's current "infrastructure crises," because it's a primary reason why the American Society of Civil Engineers labels 80,000 US bridges as "functionally obsolete," Schwartz notes. America faces a bridge maintenance crises, but it is much more manageable than the engineering profession would have us believe. The problem with standards includes all highways as well, and we'd be better off if many of the standards and assumptions of traffic engineers changed. For that to happen, the profession will have to own up to its mistakes to a much greater degree.

Street Smart, a first-hand account from a contrarian engineer who rose to the top of his profession when the automobile was king, is a strong step in that direction. 

Because Schwartz was in the right place at the right time, he was given a lot of responsibility at a young age. When a section of the elevated West Side Highway collapsed in 1973 under the weight of a 30-ton truckload, the task of what to do with the traffic fell to Schwartz, who was in his mid-20s. "The predicted traffic disaster never appeared. Somehow, those eighty thousand cars went somewhere, but to this day we have no idea where many of them went."

This gave Schwartz a lesson in "induced demand" and the resilience of the grid. The West Side Highway was eventually rebuilt as an at-grade boulevard. "This wasn't obvious at the time, but unbuilding a replacement for the West Side Highway was a huge financial boon to the cash-strapped city, and not just because we avoided spending tens of millions of dollars in construction costs." The city avoided ongoing maintenance costs and created real estate value along the new boulevard.

West Side Highway as a boulevard, at the Jacob Javits convention center.

Schwartz offers sharp observations on the hottest trends in transportation technology—on-demand vehicles and self-driving cars. In Manhattan's Midtown core, algebra and geometry proves that at any given time. only about 5,200 vehicles are in motion during the busiest morning hour—the maximum number of vehicles that would allow any movement at all is 9,000. Every city has a similar vehicles-in-motion maximum, which has important implications for Uber and Lyft. "To the degree that their appeal depends on increasing the supply of cars to the point that no one is every more than a few minutes away from a roving driver waiting for a smartphone to put driver and rider together, the model is fundamentally unsustainable." 

Although Schwartz praises Google's technological achievements, the company and news reports are not giving the public the full story. Google's system is not updated enough, he notes, to account for every lane closing, every pothole, every temporary light—it cannot tell between a deer, a dog, or a five-year old child. Successful test drives are preceded by dedicated vehicles that upload information on routes, he explains. "In a way, driverless cars seem like a Rube Goldberg approach to getting from here to there. For short trips, walking and biking are safer and healthier than Google's most ambitious vehicle; for many longer ones, so is transit."

Schwartz is one of the smartest transportation engineers around, and Street Smart is a brilliant book for our times that should be widely read by transportation engineers and planners.

Robert Steuteville is editor and executive director of Better Cities & Towns.