Chicago's Yellow Light Intervals Generating More Fines

Cameron Aubernon
by Cameron Aubernon
chicago s yellow light intervals generating more fines

Ever notice how the traffic lights in Chicago switch from yellow to red quicker than in other cities? That’s because the city changed the formula.

FiveThirtyEight reports the formula — yellow change time = 1 + (1.47 * Approach Speed) / (2 * Deceleration Rate) — was altered to increase the chances of a driver running a red, an act that would then be caught by the city’s red-light cameras, thus leading to a fine for the driver.

The formula used in Chicago is the one prescribed by the American Association of State Highway and Transportation Officials, which sets the deceleration rate at 11.2 feet/second over the standard formula’s 10 feet/second. The city also calculates yellow intervals by the posted speed limit, instead of the Federal Highway Association’s 85th percentile speed of real drivers, with the option to add 5 mph to the speed-limit yellow interval, as well.

The yellow interval — and its tie to the red-light cameras — have been a factor in Mayor Rahm Emanuel’s fight for another term in office, which has since entered the runoff phase after his campaign failed to gain an outright majority Tuesday. Emanuel’s support for the cameras runs in opposition of the city’s residents, 66 percent of whom believe the technology isn’t helping traffic safety in the least.

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  • -Nate -Nate on Feb 27, 2015

    Almost every where there are traffic cameras , this short yellow light problem crops up because the cameras are provided under contract on a per ticker portion of fee sharing of the Dollars gained . Obviously this is a scam and posting it here and showing up at your Town Hall , writing letters etc. really does work to get it changed . Good on you for spreading the word . -Nate

  • Ugliest1 Ugliest1 on Feb 27, 2015

    One advancement that is happening that I really like is the countdown timers on the pedestrian signals replacing mere flashing hands. Where I live (not Chicago) they really help drivers, from a long distance away, understand how close the green light is to turning yellow. Helps reduce almost to zero the "do I stay or do I go" episodes. Of course, that presumably reduces the revenue-generation probabilities of the enforcing jurisdiction, so I hope the municipalities where I live don't see this article.

    • SC5door SC5door on Feb 27, 2015

      I don't understand on how people continue to get red-light tickets even with most if not ALL the intersections in Chicago have that little gem on the side. If it's less than 3 seconds I let off the gas and coast up to the light. (It's called get your vision checked people!) I'm not in THAT big of a hurry to run down people, cause an accident, or get a ticket just because I don't want to sit at a red light.

  • SunnyvaleCA SunnyvaleCA on Feb 27, 2015

    It's hard to claim "safety" if you're also reducing the light times. Welcome to "policing for profit." Near me, the city of Milbrae dishes out fines north of $650. For my part, I'm currently fighting a ticket for parking in a handicapped parking spot that did not have a sign! (Fortunately, its a mere $317.)

  • JimC2 JimC2 on Mar 01, 2015

    Whoa... A story about crooked politics in the "New Orleans of the north." Where did I put my shocked face?