- A Sweden-born engineer who campaigns for longer-lasting yellow traffic lights has won the attention of an important traffic organization.
- Red-light cameras have motivated municipalities to shorten yellow lights to barely legal standards that likely cause more accidents.
- Engineer Mats Järlström seeks to update the equation that many cities use to calculate yellow-light length.
On Halloween 2013, I was driving home after an early release from my job at the time. At a major intersection here in Chicago, I was driving below the speed limit (Chicago traffic!) through a yellow light just as an oncoming driver decided to turn left without the right of way. She crashed into me and totaled my car; I was fine besides an airbag burn on my arm, but my car was past the sell-by date for repairs being worth it.
Afterward, a police officer said to us both, "A yellow light is not a race." The other driver was a busy mom with her toddler in a car seat, and her car was mostly unharmed. We shared Halloween candy from a plastic pumpkin in her trunk.
A yellow light may not be a race, but it's definitely a big problem. And Sweden-born engineer Mats Järlström is a crusader trying to fight for the solution.
When Järlström's wife got a red-light ticket in 2013, he examined the footage and fought the ticket in court based on his observation that the yellow light wasn't long enough. His city of Beaverton, Oregon, had a law on the books requiring a 3.5-second yellow light. Before Beaverton, cities like Dallas, Chattanooga, and Nashville had already been caught shortening yellow lights by 2008.
Since then, Chicago faced and lost a giant lawsuit for its combination of record-short yellow lights and wild number of red-light cameras that brought in $285 million between 2011 and 2015. Chicago chose to scrape the very bottom of the federally regulated range for yellow lights in a city with the third-worst traffic in the nation.
Now, the IEEE magazine Spectrum reports the latest good news for Järlström: The Institute of Transportation Engineers (ITE), which has a chapter in every state, has agreed with his report that the existing yellow-light calculus is not adequate.
This has been a long process for Järlström, who was a credentialed electrical engineer in Sweden before moving to the U.S. in the early '90s. When he began doing research and writing inquiries about yellow lights, Oregon's governing body of licensed engineers fined him for claiming to be an engineer. He sued them, and won, for violating his freedom of speech. (Finally, an application that really involves the legal definition of free speech.)
Järlström basically appointed himself as the Erin Brockovich of yellow-light law, chasing leads and asking for help from experts until he finally got their attention. Making inroads with the ITE is a great start. In a 2014 article, Gizmodo shared a 2012 Transportation Research Board survey that showed 40 percent of cities used ITE-designed metrics and equations to calculate their yellow-light length. ITE's own 2017 survey showed similar numbers.
In consulting with ITE members and even speaking at one of their conferences, Järlström is pushing for one specific change to the kinematic equation. The shorter yellow lights to increase ticketing are a safety problem in general, but in Järlström's wife's case, her issue was that she was waiting to turn during a yellow light.
Because of the different speed and approach to making a left turn, the equation didn't assign enough of a time value to account for this slower part of intersection traffic. Järlström's work doesn't seek to replace the ITE's existing equation at all, but instead add mathematical nuance that will include people waiting to turn.
"I want it to be a collaboration. The common goal is to improve traffic safety and fairness in intersections," Järlström told Spectrum.
From: Popular Mechanics