This article was originally published on Common Edge.
In 2007, New York City Mayor Michael Bloomberg proposed congestion pricing for Manhattan. The state legislature rejected the plan. Fifteen years later, we’re still debating the idea, fiddling while the planet burns.
The newest problem is that a new environmental study and traffic model from the MTA, The Central Business District Tolling Program Environmental Assessment, says that what’s good for 1.63 million residents of Manhattan and the planet, in general, will increase the pollution in the already unhealthy air in the Bronx. Yes, that’s a problem. Turning the perfect into the enemy of the good is also a problem. We need a plan that benefits all.
Having spent decades in the fields of urban design and street design, I question how much we can rely on the dire predictions in a study prepared by traffic engineers. I’m not well qualified to give the study a peer review, but consider a different study at the University of Aalborg in Denmark, which found “with very high statistical significance that [traffic engineer] forecasters generally do a poor job of estimating the demand for transportation infrastructure projects.”
“For 50% of road projects,” the study concluded, “the difference between actual and forecasted traffic is more than ±20%; for 25%, the difference is larger than ±40%.” Applying that to the current congestion pricing study, the worst-case projection is that truck traffic will increase by 5%. That’s far less than the margin of error found by the Aalborg study in most cases.
Most traffic models assume driving will always increase. Why? Because they’re made by traffic engineers, whose job is to claim our streets for the free flow of ever-increasing traffic.
In transportation planning—i.e., traffic planning—that’s a good thing. Better living through happy motoring. As was claimed decades and decades ago, what’s good for General Motors is good for America. But it’s important to remember that this profession, traffic engineering, which is only 100 years old, gave us a revolutionary new transportation system that kills over 40,000 Americans every year. And that system, based on the idea that everyone will drive everywhere for everything, has been America’s biggest contribution to climate change and global warming.
This sounds harsh, I know. But some of my best friends are traffic engineers, and they’re the people who taught me this. “Recovering traffic engineer” Chuck Marohn says, “the underlying values of the transportation system are not the American public’s values. They are not even human values. They are values unique to a profession that has been empowered with reshaping an entire continent around a new, experimental idea of how to build a human habitat.”
So if you want to know how congestion pricing will affect “Regional VMT” (the number of miles people drive every day in the greater New York area, for example), are traffic engineers the best people to ask? Maybe not.
Traffic modeling is a black-box process that gives us opinions and projections as facts. Traffic modeling is not a science. The conclusions that come out are only as good as the assumptions made in the beginning. In the case of the Central Business District Tolling Program Environmental Assessment, we don’t know what those are.
Imagine the study had been made in December 2019. The black-box input would not have included the Covid-19 pandemic, the change in remote office work and commuting patterns, a dramatic rise and fall in gas prices, or the tipping points that change can produce. In 2020, a 40% decrease in driving produced the cleanest air in American cities in more than a century. Satellite photos showed a change in air quality at the North Pole. Quieter, emptier streets in Manhattan, where emergency vehicles could move again, produced more deaths rather than fewer. Why? A small but significant number of drivers and moped-share riders started acting like maniacs, running red lights and driving at high speeds.
In my Upper West Side neighborhood, near the 96th Street exit from the Henry Hudson Highway, the number of suburban drivers who wanted to park for free on the streets increased slightly, but that small increase made it almost impossible to find a free space between 10 am and 5 pm. Traffic modeling might say the increase was small and stop there, concluding the effect would be minimal. But the small number radically changed parking.
I live on one of the narrow local roads on the east side of Riverside Drive. In the early months of the pandemic, traffic came roaring up the hill in waves every time the light at the end of the off-ramp changed. The streets had less traffic than a few months before, but many drivers brought suburban road rage to our urban streets. People died. No traffic model made in December 2019 would have predicted that.
The traffic models that say congestion pricing will increase the number of trucks polluting the air on the Cross Bronx Expressway may be right. Or they may be completely wrong. There are reasons to think that worries about congestion will decrease traffic.
Traffic engineers brought us a phenomenon known as “induced demand.” When they add lanes to a highway to ease congestion, over time the lanes become crowded with drivers attracted by the additional capacity. “Reduced demand” is the opposite. When lanes are reduced, or an urban highway is removed, traffic frequently “evaporates.”
Before lanes can be removed or a highway torn down, traffic engineers challenge people to show what will happen to the traffic. Words like “carmageddon” and “carpocalypse” appear in the press. But the truth is that no one has ever made a model that shows why it will disappear. Usually, it does, however.
Self-described “recovering traffic engineer” Chuck Marohn says, “the underlying values of the transportation system are not the American public’s values. They are not even human values.”
People find other ways to get where they’re going. The Regional Planning and Development Agency in Paris and the French Ministry of Transport have studied this phenomenon: “The reduction of traffic is mainly due to behavioral change: people start adapting to the new spatial configuration. The behavioral changes that bring ‘traffic evaporation’ are: change of itinerary and of schedules, the frequency of travel, the mode of transport (shifting from cars to two-wheeled vehicles, bicycle, etc.), but also car-pooling, new family organization, moving or working remotely.”
I was in London the day the city introduced congestion pricing in 2003. The overnight change in traffic was amazing. Since then, a variety of factors have brought back a lot of the traffic, including two important factors that weren’t in any traffic model at the time: the rise of Uber and Lyft, and the number of vans and trucks delivering orders from the internet.
Congestion zones always require adaptation. In the case of New York, we will have to monitor and, if necessary, modify truck traffic in the Bronx. London governments and agencies discussed reducing London traffic and pollution for 40 years. When they finally introduced congestion pricing, it became one of the most popular political acts in the history of the city.
Twenty years later, we know much more about climate change and the problems caused by driving. We need to get off our bureaucratic a**es and start the experiment of reducing traffic. Two weeks after congestion pricing starts, every progressive politician in New York will want to claim credit for the change. Then we can fix the problems like increased pollution in the Bronx (if there is increased pollution), the number of Ubers on our streets, and fine-tuning the regulations for those who need free access by car.
