By on September 26, 2011

Photo enforcement advocates downplay the benefit of increased yellow time in addressing the problem of red light running. New evidence from Arnold, Missouri shows that red light cameras continue to flash at a much lower rate since the state mandated longer signal timing at a number of photo-enforced intersections.

Arnold was the first jurisdiction in the Show Me State to allow a private company, American Traffic Solutions (ATS), to mail traffic tickets to residents. Since 2005, ATS has handed out more than 30,000 tickets worth over $3.1 million. In 2010, tickets were being pumped out at an average rate of 800 per month. With longer yellows, that figure averaged just 113 through July and August using the most up-to-date data available.

Timing changes were made at and near the red light camera intersections. Yellows increased from 4.0 to 5.0 seconds at three intersections along Missouri Route 141 on February 24. Smaller changes were made on April 15, including a boost from 4.0 to 4.4 seconds at northbound 141 and US 61/67, a 4.0 to 4.5 second change at northbound US 61/67 at Rockport School, and from 4.0 to 4.7 seconds at southbound Vogel Road at Richardson Road (4.3 seconds at the northbound approach).

While a difference of 0.4 to 1.0 seconds in the length of the yellow light might seem insignificant, the extra margin of safety is critical. The vast majority of straight-through red light “violations” happen when a driver misjudges the end of the yellow light by less than 0.25 seconds — literally the blink of an eye (view Texas Transportation Institute (TTI) chart). With those longer yellow times, the city and ATS are losing $780,000 in annual revenue — an 86 percent drop.

The Insurance Institute for Highway Safety’s former top researcher, Richard Retting, argued strongly against the use of yellow signal timing beyond the bare ITE minimum values. His research is cited by the Federal Highway Administration (FHWA) in its “Toolbox of Engineering Countermeasures,” which is used by cities to set up intersections prior to the use of automated ticketing machines.

“Present thought is that longer intervals will cause drivers to enter the intersection later and it will breed disrespect for the traffic signal,” the FHWA document explains. “The tendency for motorists to adjust to the longer interval and enter the intersection later is referred to as habituation. The before-and-after study by Retting and Greene evaluated the presence of habituation to the longer yellow… The authors concluded that habituation to the longer yellow did exist….”

Retting is now employed by a red light camera company.


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6 Comments on “Missouri: Violations Still Down with Longer Yellows...”

  • avatar

    When you’re driver a commercial vehicle, or your own vehicle with something large in tow, or a antique vehicle that has no power brakes, the longer yellow lights make all the difference. I swear, they time these things for a modern compact-vehicle that can stop on a dime, and ignore the rest of the vehicles on the road. When I’m driving my new Jeep towing my travel trailer (equipped with double axle-brakes to boot) there are many lights I just can’t make in time. I’ve driven much larger trucks too, and I see them constantly run lights. I wonder how the cameras handle those situations? People in my field have to maintain a safe driving record; the cost of a traffic violation can go much further then a small fine and insurance hikes. Sucks when “officials” make it damn near impossible for you to drive safely, especially when your career depends so much on it.

    A year ago my wife got ticketed at a local intersection. Was a favorite place for cops to bust people. It was a odd intersection, which had a longer-than-usual distance to cross through. I came through that same intersection after her incident, driving my antique Jeep CJ (large tires, no power brakes). I was doing the speed limit, light turned green-yellow-red. I ran it completely; there was no way I could stop that vehicle in time. Luckily officer McLaw wasn’t sitting there, although I would of made a video of the short timer and brought it to court if I ended up in the same situation as her.

    They let her go to traffic school, so nothing on her record. That was still after the cop marked the wrong court location on the ticket, which was hell in and of itself for her. Not to mention, she “ran the light” when it was raining and the road was soaked. She met a city attorney in court that got cited shortly after her. Same story, same jerk cop.

  • avatar

    It is all about the money.
    This is not about safety.
    Red lights do not get respect when drivers know they are used to collect money.

    Focus on safety. Does a longer yellow make an intersection safer? Does it do anything other than prevents a guy from collecting a profit?

    Traffic lights are not to be used as toll booths. Red light cameras are unethical and do not make intersections safer.

  • avatar
    Diesel Fuel Only

    And how much of that money goes to overhead? Arnold Missouri is one of 13 (THIRTEEN!) incorporated towns in Jefferson County.

    All of Great Britain, population 62 million, has 52 police departments total (and they all drive BMW’s by the way), most of which are organized regionally.

    Here in my little corner of the south, we (population 20,000) have a police chief and our own force. The next town up (3 miles north), population 1500, has a chief and a force that collects $1.5 m. in tickets on the interstate every year. The next town west, population 7500, has its own force. The next two towns south (6 miles south) each population 1500 and each directly adjacent to each other (town halls are 1.7 miles apart, not kidding!) has its own force with its own chief. Another little town, population 900, six miles southeast has its own force and the next town six miles down that road has its own force, too. The two towns to the east, each about 1000 people and the nearest one only four miles from here, both hand out speeding tickets on the US highway. They each have their own police chiefs and police departments.

    And of course we have the Sheriff patrolling the unincorporated areas and the state police.

    The next county down has one city with more than half the population in the county (120,000 out of 200,000) and yet there are four directly adjacent towns in that county each with their own chiefs, each with their own overhead. The next town over their county line is only five miles down the road, population 3000. It has its own department and all the fixins’ as well.

    It’s time for more regional government in this country. We can’t afford this overhead and we can’t afford small-time petty fiefdoms anymore.

  • avatar

    Blindly adding seconds is a half-assed way to correct short traffic lights in clear violation of the FHWA MUTCD.

    There is a formula. It is referred to as the Kell and Fullerton Light Duration Equation. The FHWA has a pamphlet you can download titled “Field Guide for Inspecting Signalized Intersections to Reduce Red-Light Running” (fguide_isirlr.pdf) It shows you how to use the formula to do the math for an intersection.

    5.8 seconds covers 85% of all normal intersections. 4.6 seconds is about the shortest you come up with for a narrower intersection. Less than 4.6 seconds? Get a hangnail in the intersection and sue the city back to the beginning of civilization.

    Dick Retting is not someone I’d want involved in anything to do with signalized intersections.

  • avatar

    The vast majority of straight-through red light “violations” happen when a driver misjudges the end of the yellow light by less than 0.25 seconds

    Here’s the problem with this approach–it is based on a person’s ‘judgment’ of when a yellow will end, in other words, it is his intention to run the yellow because he believes he can make it. What happens when drivers become accustomed to longer yellow lights? Will they add in that extra time to their judgment of whether they can make it? I don’t know, but given my knowledge of how people gun it to make yellow lights, my guess is yes.

    (I’ve noticed that drivers whose first instinct is to stop at yellows don’t bother ‘judging’ whether they can make it, but whether they can physically stop short of the intersection. Also, drivers with this attitude will look for clues for the end of the green light, such as cross walk lights changing, thus they are prepped for stopping before the light even turns yellow.)

    I disagree with having a private company operate RLCs. I disagree with them taking revenue from citations. I disagree with them having any say in light logic or durations. Yellow lights should be long enough for safety, but short enough that it is not a hindrance for traffic throughput. I would support a new concept of light that gives indication of how long it has left in its current state (e.g., how long before a red turns green, how long before a green turns yellow). Better information leads to better decisions. However, there are those who are not interested in making good and safe decisions, and a solution needs to be found that eliminates that form of thinking.

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