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Unintended Consequences For Traffic Safety Feature

An anonymous reader writes: Traffic engineers had a problem to solve: too many pedestrians were getting hit by cars while using the crosswalks at intersections because they didn't know when the 'WALK' sign would change. Their solution was simple: implement a countdown timer. Countless cities have now adopted these timers, but it turns out to have an undesired consequence: motor vehicle crashes are actually increasing at intersections where the countdown timer is used. Researchers think this is because pedestrians aren't the only ones who see the timers. Drivers see them too, and it provides them with information on when the light will change. Then they anticipate the change by either speeding up to beat a change to red light, or anticipating a green light in order to get through before the pedestrians can move into the road. The researchers suggest finding some way to hide the countdown from the drivers, perhaps through the use of an audio countdown that would be difficult to hear from inside a car.

9 of 579 comments (clear)

  1. Not for deaf/hard of hearing... by Anonymous Coward · · Score: 5, Insightful

    Please don't do an audio countdown. It doesn't work for us hard of hearing people.

    1. Re:Not for deaf/hard of hearing... by nospam007 · · Score: 5, Insightful

      "Please don't do an audio countdown. It doesn't work for us hard of hearing people."

      Where I live, they have audio ticking for blind people. They make a ticking noise when it's green for pedestrians.
      Although some of them seem to be made for almost-deaf blind people, since it's very loud even during daytime.

    2. Re:Not for deaf/hard of hearing... by macklin01 · · Score: 4, Insightful

      I've encountered these, and I'm told they're pretty loud.

      I'm a fairly young guy (37 yo) with perfect hearing below about 1500 Hz, and almost zero hearing above 2000 Hz. To me, these loud clicks are tough to hear unless close up.

      I run into the same problem with high-pitched fire alarms (most of them), the "you left your headlights on" beep, seat belt beeps, kitchen timers, the little beep on my FasTrak transponder, etc.

      This is probably a widespread problem--we tend to lose hearing in the higher frequencies first. The solution isn't to use annoying high pitches and make them louder; the solution is to use broader frequencies or use lower pitches that more people can hear.

      Please keep this in mind when you're considering using a little chirpy piezoelectric in your next circuit project ...

      --
      OpenSource.MathCancer.org: open source comp bio
  2. sound and sides by thaylin · · Score: 5, Insightful

    Make angled sides on the signal to that you can only see it from like a +/- 5 degree angle, or less, and use sounds for the blind.

    --
    When you cant win, ad hominem.
  3. OR by Murdoch5 · · Score: 5, Insightful

    Drivers need to pay attention to the road, there is no excuse for hitting a pedestrian in a cross walk or for a car to hit car at a cross walk. Drivers need to grow up, pay attention and stop blaming everything but the lack of driving ability.

    1. Re:OR by michelcolman · · Score: 4, Insightful

      That's a great solution, I wonder why nobody else has thought of that!

    2. Re:OR by BitZtream · · Score: 5, Insightful

      While you are 100% correct, I was always taught to pay attention to my surroundings ... and that includes keeping an eye out for a ton or two object moving at a decent speed.

      One could argue that in most cases, a pedestrian paying attention could have avoided getting ran over if they'd pulled their heads out of their phones long enough to look around them.

      --
      Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
  4. Audible warning by dywolf · · Score: 5, Insightful

    In atlanta at least, the countdown is already accompanied by an audible chirp.
    Intended for blind or otherwise disabled folks (except deaf folks, naturally), it also serves as a cue for regular folks as well to hurry up on some of hte larger/wider intersections.

    Really all that should be fixed is to put a bigger gap between the countdown reaching 0 and the light actually changing. My experience with signal timing (and this is my trafic engineering schooling showing through) is roughly half-half: about half the intersections I saw with the countdown change immediately, others still have the standard 4-5 second "intersection clearance delay" between the countdown ending, and the light actually changing. The clearance delay exists for obvious reasons to put a delay between one side turning red and another green. It should simply also take the crosswalk into consideration as well as a best practice.

    --
    The guy who said the election was rigged won the presidency with the second-most votes.
  5. Re:The problem with traffic engineers... by twdorris · · Score: 4, Insightful

    As it turns out, people are stupid.

    Truer words have never been spoken. People are stupid and you can't fix stupid. You'd think they'd weed themselves out eventually, but as it turns out, we're all people. And we're all stupid. We're just stupid at different times.

    I've nearly run into the back of someone at a stop light when they started rolling forward and then suddenly slammed on the brakes because they didn't see a car coming into the intersection. I was glancing around checking for traffic I might have been concerned with and nearly ran into the back of him because I just assumed he was going to continue rolling forward like the hundreds of others before him I had been behind at other intersections.

    A single moment of inattention and a single false assumption nearly caused a wreck. I was stupid. We're all stupid. We all need some engineered help against stupid from time to time. A sensor that detects an impending crash with something right in front of me would have helped. Lots of cars have these things now. That's an engineered solution to a moment of stupidity.

    Not everything can be fixed with engineered solutions, but we can't assume modifying behavior is a fix-all either. In fact, I would give behavior modification a far less chance of success given how random and clueless we meatbags are.

    So I vote for more engineered solutions, not less. But the solutions need to involved some human behavioral analysis as well. I mean who in their right minds couldn't have predicted that passing motorists would see these count down times and use them to speed through intersections? And who wouldn't have predicted that this would leave to an increase in accidents on average? Duh. That should have been taken into account and a different solution should have been investigated.

    All that said, I also feel like we need to define some acceptable limits here. I mean we can't go making every single intersection 100% secure. If some accidents are happening at an intersection, let's talk about the *rate* and decide if that's just an acceptable rate or not. The fact that there are accidents or that accidents are happening a little more often now than they were before is a little meaningless without numbers to compare to. I find that we have FAR, FAR too many laws and regulations trying to bring fatalities and liabilities and accidents to near zero already.