Citizen Scientist Challenges Math Behind Red Light Camera Tickets A man in Oregon is challenging the math behind red light camera tickets. Mats Järlström calculates that drivers who end up in an intersection when the light goes yellow can be trapped in a no-win dilemma, particularly if they are making a turn. NPR's Kelly McEvers talks to Aarian Marshall, who wrote about the case for Wired magazine.
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Citizen Scientist Challenges Math Behind Red Light Camera Tickets

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Citizen Scientist Challenges Math Behind Red Light Camera Tickets

Citizen Scientist Challenges Math Behind Red Light Camera Tickets

Citizen Scientist Challenges Math Behind Red Light Camera Tickets

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  • <iframe src="https://www.npr.org/player/embed/526931921/526931923" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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A man in Oregon is challenging the math behind red light camera tickets. Mats Järlström calculates that drivers who end up in an intersection when the light goes yellow can be trapped in a no-win dilemma, particularly if they are making a turn. NPR's Kelly McEvers talks to Aarian Marshall, who wrote about the case for Wired magazine.

ROBERT SIEGEL, HOST:

It's a dilemma for anyone. You're driving, approaching an intersection. You're right up on it, and the light turns yellow. Do you have time to stop or should you push through? And what if you have to turn left and you're stuck waiting as the light turns red? Well, that no-win scenario is particularly troubling if there's a red light camera. And we're going to hear the story now of a man in Beaverton, Ore., who decided to fight the system with math. Aarian Marshall wrote about it. She covers transportation for WIRED magazine and joins us now from San Francisco. Hi.

AARIAN MARSHALL: Hi there.

SIEGEL: Man at the center of this story is named Mats Jarlstrom. Tell us about him and how he came to challenge red light tickets and what it has to do with yellow lights.

MARSHALL: Sure. So Mats' wife was driving through an intersection one day. She made a turn, and she got caught by the red light camera there. You know, you and I might go into traffic court, and we'll pay our fines but not Mats. He has a background in engineering. He went out. He taped the signal where his wife got a ticket, and he discovered that there was something a little off about it.

He did a little more research, and he found out that there's actually a formula recommended by the big engineering professional group in the U.S. that they use to time lights all over the country. So he figured out that there might be a little problem with this formula, kind of misapplied.

SIEGEL: You write the history of this. It dates back, I gather, to the 1960s when General Motors did some calculations about how long it takes drivers to react to a changing light. What is the standard?

MARSHALL: So what Mats discovered is that it only accounts for cars that are going straight through. So if you're making a turn, you have a much better chance of hitting the red and either, you know, getting a red light ticket, which is unfortunate, but the worst possible outcome is that you actually get hit by a car going the other way.

SIEGEL: So did Mats Jarlstrom then go to court and say it wasn't my wife's fault, it was these physicists from the 1960s?

MARSHALL: That is exactly what he did. He went to traffic court, and the judge there just kind of threw him out, and his wife ended up having to pay that ticket. So he went to the Oregon Board of Examiners for Engineering and Land Surveying. That's the big body that oversees all this stuff in Oregon. They responded by actually fining him $500 because he represented himself as an engineer even though he's not licensed to practice in Oregon.

SIEGEL: And is anybody reviewing these algorithms to, perhaps, make them a little longer given how many people are trying to turn left through a yellow light?

MARSHALL: Yeah. So what happened with Mats is he's actually suing the Oregon Board of Engineering for infringing his First Amendment rights to identify himself as an engineer. Meanwhile, the Institute for Transportation Engineers actually says that they're taking a pretty close look at these formulas to figure out if they have been misapplied. And they might come out with a kind of new standard for yellow light signal timing. And hopefully that will end with us getting fewer red light tickets and also just safer roads for everyone.

SIEGEL: Aarian Marshall writes about transportation for WIRED magazine, and her story about one man's quest to right the wrongs of red light cameras and yellow lights can be found at wired.com. Aarian, thank you.

MARSHALL: Thank you.

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