Posted by This weekend, Los Angeles will close a 10-mile stretch of the 405 freeway for 53 hours so work crews can conduct demolition that will enable widening of the freeway. Locals are referring to the planned closure as “Carmageddon,” anticipating gridlock on nearby roadways that remain open. The hope is that the short-term pain will bring relief of chronic traffic congestion once the widening project’s finished.
Unfortunately for hopeful Angelenos, adding more road space probably won’t relieve congestion. NPR’s Guy Raz spoke to University of Toronto economist Matthew Turner, co-author of a study that analyzed traffic in 228 US cities, who reported that 1% more roads means 1% more driving. Turner also had disappointing news for hopeful public transportation advocates like me: More public transportation doesn’t decrease traffic congestion, either. Here’s a bit of Turner and Raz’s conversation (transcription errors are mine):
Turner: What we find is that as you increase a city’s stock of light rail or bus cars, that there’s no impact on the amount of driving. That sounds sort of surprising, but it’s logically consistent with the other result that we have about the effect of roads on driving. What we find is that as you add roads to a city, those roads get filled up, so there are people waiting to use the capacity …
Raz: It’s almost like there’s a long line of people waiting to use that space on the freeway. The minute you put someone in a bus or a metro train, someone else is just going to take their space on the roads?
Turner: I think that’s right. There’s a lot of people out there trying to decide whether to make one more trip to the store or drive a little further to work. As you add a little bit more capacity, it gets filled up.
Tanya Snyder of Streetsblog Capitol Hill interviewed Turner several weeks ago and read the new paper, soon to be published in the American Economic Review, he co-authored with Gilles Duranton. Snyder writes:
They didn’t find that transit reduces congestion. But that doesn’t mean that metro areas shouldn’t build transit as a way to maximize the efficiency of their transportation networks, they say. Turner said transit is a good way to get more “person-miles” out of roads.
I’d also add that whether or not public transportation reduces congestion, it’s important for people who don’t drive cars. There are many reasons people don’t get behind the wheel – age, physical limitations, dislike of driving stress, the high costs of car ownership, or a desire to consume alcohol, send text messages, or do other things that impair driving ability. Plus, using public transportation instead of driving a car can allow people to get more physical activity as they walk to and from stops.
(Since there’s a common misconception that transit advocates want to take away everyone’s cars, I’ll also add that there are plenty of times when driving a car might be a better option than taking the bus – for instance, when a destination is poorly served by public transportation, when the trip occurs during hours of little or no transit service, when hauling bulky items or squirmy children, or when a person has physical limitations that would make it hard to walk to a stop, stand at a stop, or remain standing in the aisle or a crowded bus or rail car.)
As worthwhile as public transportation is, though, Turner and Duranton’s research found that it doesn’t reduce traffic congestion. Since building more roads doesn’t solve this problem, either, that leaves us with congestion pricing as the solution. Tolls on cars entering central areas during peak times have successfully reduced traffic congestion in London, Singapore, and Stockholm – and Turner told Raz that Stockholm saw a dramatic reduction in peak travel time in response to a relatively low fee. You can read more about these cities’ experiences in this report prepared by KT Analytics for the US Department of Transportation’s Federal Highway Administration.
New York Mayor Michael Bloomberg tried to move toward congestion pricing for Manhattan, but didn’t succeed. As Turner pointed out to Raz, “people don’t want to pay for something that they’re used to getting for free.”
Raz brought up the concern that lower-income households will find it harder to afford tolls; Turner agreed, and added that poor workers tend to have less discretion about when they get to work. (One option for avoiding a toll is to travel before or after peak times, but it’s often higher-paid employees who have the flexibility to work from, say, 7am – 3pm or 10am – 6pm.) The NPR segment doesn’t delve much farther into this issue, but the KT Analytics report notes that London and Stockholm both use toll revenue to fund improvements to public transportation. Better public transportation, perhaps along with subsidized fares, could make it easier for those who can’t afford the tolls to take a train or bus instead – although, again, public transportation still won’t work for every person in every situation.
Given that traffic congestion has large environmental, time, and economic costs, and that other attempted solutions haven’t succeeded, it seems like it would be worthwhile to figure out how to make congestion pricing work.
July 11, 2011
July 11, 2011
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