Traffic signals could be screwing you over because even stoplights can't do math

Those stoplight cameras that catch us committing the tiniest traffic infractions might not be as accurate as we've been led to believe, according to a very persistent Oregon resident whose nearly four-year battle against the system was recently profiled by Wired. It's not the cameras themselves, it's the math controlling the timing of stoplight signals that's the alleged root of the problem, forcing drivers to make a split-second decision when caught in a yellow light.

Mats Järlström started his fight against traffic signals after his wife Laurie was slapped with a ticket for turning right through a red stoplight back in 2013. The Swedish-born former electrical engineer claims the timing system that controls the signals is fundamentally flawed and unfair, not giving drivers enough time to react to the changing yellow light. He contends the flaw should make the penalty given to his wife — and therefore, similar tickets given to thousands of other drivers across the country — null and void.

Järlström's campaign against the traffic signals has culminated in a civil lawsuit against the Oregon State Board of Examiners for Engineering and Land Surveying (OSBEELS), which he says attempted to block his attempts to present evidence of the system's flaws and violated his First Amendment rights.

After Laurie's ticket, Järlström recorded the Beaverton traffic signal that dinged her to analyze the footage. He found that the yellow lights were 0.3 seconds shorter than the state authorities claimed, and concluded that drivers turning right through the signal are more likely to be trapped in a "dilemma zone" — the split-second when drivers are forced to decide whether to pump the breaks or charge through the changing light.

When Järlström submitted his findings to OSBEELS in 2014, it wasn't exactly received kindly. Instead, the Board opened up a two-year investigation into Järlström, concluding that he'd improperly identified himself as an engineer and slapping him with a $500 fine. He responded with the civil suit, telling Wired, "I want to be able to describe myself as who I am, to be able to talk about myself freely.”

But Järlström isn't the only person to raise concerns about the formula that creates the dilemma zone, which has been widely applied as the standard by traffic engineers across the country since its introduction in 1960 by a trio of GM physicists. The Institute for Transportation Engineers (ITE) recommends its use, but the last of its surviving authors, Alexei Maradudin, pointed out its flaws for drivers in a turn lane as recently as 2015 in a letter to the organization.

A separate 2012 study also found that right-turning drivers are caught in the dilemma zone as often as 15 percent of the time they approach a yellow light, and that longer vehicles and bad weather throw the formula off as well.

The nearly 60-year-old system is due for a shakeup, and one could be coming soon. The ITE is working through an extensive peer-reviewed process, due this fall, to update the guidelines it recommends to control traffic signal timing. Järlström’s work will be factored into the final report, according to Wired. “ITE is always open to receiving comments and new research knowledge as part of the development process for our recommended practices,” the organization's head of operations, Douglas Noble, told the site.