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The Unintended Consequences Of Trying To Fix Traffic

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The Unintended Consequences Of Trying To Fix Traffic

The Unintended Consequences Of Trying To Fix Traffic

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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This is HIDDEN BRAIN. I'm Shankar Vedantam. If you live or work in a city, sitting in traffic is probably a big part of your life.


UNIDENTIFIED MAN: About 15, the Lincoln about 20 to 30 out. On the inbound side, we got about a 20-minute delay.

VEDANTAM: You're in Washington, D.C. We take perverse pride in having some of the worst traffic in the United States. But on a global scale, D.C. has nothing on London or Istanbul, Rio or Mexico City. On today's episode, we're going to explore all kinds of interventions that can make traffic better. We're also going to look at the interventions that are supposed to make traffic better but don't.

DANIEL PINK, BYLINE: I feel like we should put together the international journal of unintended consequences...

VEDANTAM: (Laughter).

PINK: ...And send them to lawmakers all over the planet.

VEDANTAM: Before we get there, we want to take you on a quick trip around some of the world's most congested cities. Producer Maggie Penman reached to NPR correspondents stationed in Asia, Africa and Europe. She's also going to tell us about a little traffic culture clash of her own.

MAGGIE PENMAN, BYLINE: So a few years ago, I'm out in LA for a couple of days for work. I'm driving a rented car, and I come up to a busy intersection, and I'm trying to turn left. I have my blinker on, I'm in the left-hand turn lane, and the light is green. But there is still tons of cars coming through the intersection. So I patiently sit there waiting my turn, and the light turns yellow, and there's still cars coming through the intersection. And then the light turns red. I think, OK, I'll just wait until the light turns green again, big mistake.

The cars behind me start honking like crazy. I can see the guy in my rearview mirror, and he's losing it, yelling, hitting his steering wheel in frustration. When the light does turn green again, I'm now determined to make this left turn. And the guy behind me turns, too, and then passes me immediately, yelling out his window and flipping me off. At the next intersection, the woman who was behind him pulls up next to me and signals for me to roll my window down. And she's this kind-looking lady, probably about my mother's age.

And I thought she was going to commiserate with me about how crazy that guy was. But no, then she starts yelling at me, too. Why didn't you go? Were you texting? What's wrong with you? So I get to the NPR West office, and I'm very shaken up, and I describe this experience to a couple of my colleagues who live and work in LA, and they're both like, oh, yeah, you probably should have gone.

AREZOU REZVANI, BYLINE: So we confirmed for you that you are indeed crazy. At least in LA you are.

PENMAN: That's Arezou Rezvani, an editor at Morning Edition who works out of NPR's LA bureau. She was one of the people I was meeting that day, and I recently called her up to try and get some insight about why my style of driving was so frustrating to LA drivers.

REZVANI: You have to kind of float in the middle of an intersection when you want to make a left or right turn. You got to wait for the cars on coming traffic to, you know, finish up, and sometimes that means making that turn on a red.

PENMAN: So wait, I was supposed to run the red light.

REZVANI: By the book, that's illegal, right? But there's just a new normal that is introduced in cities like Los Angeles, and you've just kind of got to go with the flow.

PENMAN: I was really curious about this new normal that Arezou was talking about, and I wondered whether other cities had unspoken rules or conventions, too.

FRANK LANGFITT, BYLINE: When you come to a light and it turns green, the automatic thing to do if you want to take a left turn is to immediately rush and take a left across three or four lanes of traffic.

PENMAN: The first person I thought to ask was Frank Langfitt, who, in addition to being NPR's correspondent based in Shanghai, has also occasionally driven a taxi around the city to find stories.

LANGFITT: It's like being in a game where anything can come at you at any time from any angle. So a stop sign, a light is not entirely relevant but not very relevant. So when I go through intersections, I look right. I look left. I look right again.

PENMAN: The norm in Shanghai is that traffic laws are more like suggestions.

LANGFITT: Here in Shanghai, there is not a lot of enforcement. And I'm amazed when I get a ticket. I was pulled over a while ago for being in the wrong turn lane, which was just kind of comical considering all the things that the cops allow people to do here.

PENMAN: But considering all of this, I was shocked when Frank told me about another norm. There's almost no road rage.

LANGFITT: As long as the cars never touch, people just let it go. And I think it's - maybe it's partly a function. I don't understand all of this, even though I've been here a long time. It may be a function that this is such a crowded country, especially these big cities on the East Coast, that if you are going to get angry about this stuff, you'd just have a heart attack.

PENMAN: In fact, he said...

LANGFITT: I'm the only one who has road rage. (Unintelligible). I'm, like, the only guy in the city who has road rage.

PENMAN: I also talked to NPR's correspondent in Nairobi, Greg Warner, and he told me Nairobi is one of the most polite cities he's ever lived in.

GREGORY WARNER, BYLINE: For instance, nobody cuts in line.

PENMAN: But when it comes to driving, Greg says, all that changes. One of the main features of driving in Nairobi, according to Greg, is that there are very few traffic lights.

WARNER: There are occasionally, like, a random traffic light you'll see, but nobody actually pays attention to it. It has no actual meaning. It just turns green and red and for no particular reason.

PENMAN: So how do people know when to go?

WARNER: It's all convention. And so in this situation, what I would think people would do is a kind of honor system. Like, OK, yeah, you went. OK, now let me go. That lane hasn't gone for a while. Like, it's just a kind of understanding, but it's actually just a complete free for all. Everybody's trying to go at once. And every four-lane intersection is like a gridlock.

And it's not just a gridlock where, you know, some cars will kind of inch forward, but it's like a twisted knot where I'm behind your bumper, and they're behind their bumper. And it's like this interlocked, you know, kind of origami or whatever.


PENMAN: I also talked to Rich Preston, NPR's producer in London, and the primary feature of driving in the UK is, of course, that you drive on the left.

RICH PRESTON, BYLINE: And as the London producer dealing with visiting American correspondents, I see this a lot is visitors to the United Kingdom stepping out into the road not looking down the road the right way.

PENMAN: Rich travels around for work and is pretty accustomed to switching sides and driving on the right. But occasionally, that rule of thumb gets him into trouble.

PRESTON: There's that mentality of, oh, I'm in another country. I'm going to have to drive on the right-hand side. I started driving on the right-hand side of the road in Ireland, even though I should have been sticking on the left.

PENMAN: And even when he's back home in London, Rich says driving can be pretty scary.

PRESTON: Because the thing about London is it's such an old city, it's really hard to make more space for all the people that are here.

PENMAN: Rich mostly cycles around the city these days, but he can still be found honking at drivers.

PRESTON: I actually bought a horn for my bike, which is this small thing that clips onto the handlebars. And it's an kind of electronic horn, and it's about 140 decibels, and it saved my life on so many occasions, I can guarantee it.

PENMAN: I asked Rich to collect some sound of his commute home yesterday, so I'm going to leave you on this somewhat shrill note.


VEDANTAM: All right, I hope you made it home safely. That's HIDDEN BRAIN producer Maggie Penman. After a short break, Dan Pink is going to be back on the show to play a round of Stopwatch Science with me. We're going to tell you about interesting social science research on what works and doesn't work to fix traffic congestion.

PINK: They found, even controlling for population growth, that constructing additional roads led to more traffic congestion, not less.

VEDANTAM: Stay with us.


VEDANTAM: Back now for a round of Stopwatch Science, I'm Shankar Vedantam. I'm joined as always by Daniel Pink, our senior Stopwatch Science correspondent. Welcome, Dan.

PINK: Thank you, Shankar.

VEDANTAM: On Stopwatch Science, Dan and I give one another 60 seconds to summarize interesting social science research. As we approach the 60-second mark, our producers will drown us out with music just like they do at the Oscars. Our topic today is traffic. You hate it. You deal with it. Maybe you are even in it...

PINK: (Laughter).

VEDANTAM: ...Right now. Today, we're going to explore what works and what doesn't work in easing congestion and improving traffic safety. Dan, if you're ready, your first 60 seconds starts now.

PINK: Well, there's one easy, if expensive, solution, and that's just to build more roads, right? It makes sense. Well, maybe not. Two economists writing in the American Economic Review analyzed two decades worth of data on U.S. commuting times and road construction. They found even controlling for population growth that constructing additional roads led to more traffic congestion, not less.

Now, what's going on here? Even though this paper is a complex bear of statistical analysis, the core explanation is simple, supply and demand. When we build roads, we increase the supply of driving opportunities. Increasing the supply of something generally reduces its price. But driving, it turns out, is extremely responsive to price changes. The lower price, that is more room on the roads, increases demand again. More individuals and commercial truckers now want to drive, and they re-congest the roads. Economists call it the fundamental law of highway congestion. More roads cause more traffic.


PINK: Unfortunately, policymakers ignore the law, and the result is futility.

VEDANTAM: So I'm guessing the solution to this is more public transit.

PINK: You would think. But what the research also shows is that adding public transportation also increases congestion for the exact same reason. It lowers the price of driving, driving responds to price changes, more people then get on the roads.

VEDANTAM: So more public transit doesn't help. More roads don't help. We just have to resign ourselves to traffic jams.

PINK: Well, what we have to do is I think we have to start thinking like economists and realize how much driving depends on price. And so the best thing to do is something that is deeply, politically unpopular, which is to raise the price of driving perhaps through congestion charges or higher tolls.

VEDANTAM: I think Dan Pink just declared for president...

PINK: (Laughter).

VEDANTAM: ...And I suspect he's not going to win.

PINK: No, I don't think so, but maybe you can win, Shankar...

VEDANTAM: (Laughter).

PINK: ...On your next 60 seconds, which begins right now.

VEDANTAM: All right, when you enact laws or make policies that affect human beings, it's often easy to forget that you're dealing with a dynamic system, which is exactly what you were just talking about, Dan.

PINK: Yes.

VEDANTAM: People adapt to new rules often in ways that policymakers don't anticipate. In the late 1980s, Mexico City was dealing with a pollution problem. Lawmakers said, let's pass a new law. They banned drivers from the road one day each week. The day you were not allowed to drive was calculated based on the last digits of your car license plate number. Boom, one simple law, 20 percent fewer cars on the road each day, right?

PINK: What could go wrong?

VEDANTAM: Exactly. Lucas Davis at the University of Michigan finds that pollution did not decline as a result of the measure in Mexico City. Why? Drivers went out and bought more cars.

PINK: Oh, boy.

VEDANTAM: If I can't drive my Toyota on Mondays...

PINK: Oh, yeah.

VEDANTAM: ...I'm going to drive my Chevy instead. Even worse, the law triggered an increase in older, more polluting cars perhaps because buying a new car is expensive, so drivers bought an old gas-guzzling clunker to drive the one day of the week they could not use their regular car. I feel that lawmakers around the world should be asked to sign the Hippocratic Oath, Dan.


VEDANTAM: First, do no harm.

PINK: Yes, exactly right. I feel like we should put together the international journal of unintended consequences...

VEDANTAM: (Laughter).

PINK: ...And send them to lawmakers all over the planet...


PINK: ...Because that's what this is.

VEDANTAM: Indeed. Now hoping that the consequences of the next 60 seconds are predictable...

PINK: (Laughter).

VEDANTAM: ...Dan, your time starts now.

PINK: We all know traffic exhaust and air pollution are harmful, but what about traffic noise? Is it a health hazard or just an annoyance? A team of British researchers looked at data on 8.6 million people in neighborhoods across London. Then they analyzed their exposure to daytime and nighttime traffic noise and compared that to a range of health data. What they found, even after controlling for race, sex, air pollution levels, socioeconomic status and other factors, was sobering.

Adults exposed to long-term daytime road traffic noise had lower life expectancies and were more likely to be admitted to the hospital for strokes than people living in quieter areas. This was especially true for elderly residents. Now the researchers found only a correlation, and the effect wasn't huge. But other evidence has shown that constantly being around loud traffic triggers stress hormones, which are linked to hypertension and occasionally death. Bottom line, that racket you here in certain areas of big cities - honking, idling, revving - maybe harming people who aren't even in the cars.


VEDANTAM: So interesting, Dan. Is it possible that this is being driven just by the fact that you have more noise pollution in urban areas and there may be other factors in urban areas that increase the mortality rate?

PINK: Well, possibly, but they actually did a good job of controlling for a lot of that. They divided up the city into census tracts and actually compared census tracts to each other. And the census tracts that had more noise had worse health outcomes, again, even after you control for the things we know drive health outcomes, especially socioeconomic status. So there was something about noise that seemed to be producing these ill effects. So let me turn it over to you for your 60 seconds, but I'd like you in light of the study to do it very quietly.

VEDANTAM: (Laughter) All right, so we've heard that noise can be bad for you, but can making noise also save your life? James Habyarimana and William Jack at Georgetown University analyzed two interventions in Kenya to improve traffic safety. The government passed a set of laws to limit unsafe driving among many bus drivers. These are vans that hold a dozen passengers. They are private versions of public transit. The laws turned out to have very little effect on road safety. What worked was a second initiative where passengers on the minibuses were encouraged to, quote, "heckle and chide...

PINK: (Laughter).

VEDANTAM: ...Drivers for unsafe driving."

VEDANTAM: Stickers on the buses said, don't just sit there. Stand up. Speak up.

PINK: Yeah.

VEDANTAM: When consumers were encouraged to make some noise, driver behavior improved radically, and many bus crashes dropped by at least 50 percent. Now we don't know what exactly drove this. Maybe people spoke up. Maybe the driver was afraid people would speak up. Whatever it was, it worked.


PINK: That is extraordinary. And I also think that we should rename this show Heckle and Chide.

VEDANTAM: (Laughter).

PINK: You can be Heckle. I can be Chide. But I - you know, I actually think a lot of this goes, you know, shows power to the people.

VEDANTAM: Yeah, can I be Dr. Heckle and can you be Mr. Chide?

PINK: Certainly.


VEDANTAM: All right, so there you have it. Building new roads can lead to more congestion, and banning people from driving can increase pollution. Traffic noise is not just unpleasant. It can have health consequences. Finally, before you pass a new law to solve a problem, try to empower the people with the problem to fix it themselves. Dan, thanks for joining me on Stopwatch Science.

PINK: My pleasure. I have to get back in my car now.


VEDANTAM: The HIDDEN BRAIN podcast is produced by Kara McGuirk-Alison, Maggie Penman and Max Nesterak. You can find us on Facebook, Twitter and Instagram and listen to my stories on your local public radio station. If you liked this episode, please leave us a review on iTunes. It'll help other people find the podcast. I'm Shankar Vedantam, and this is NPR.

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