Fallacious/Unreliable Strategies for Crossing Streets
with no Traffic Signal or Stop Sign


The following street-crossing strategies are based on erroneous assumptions. Using these strategies not only provides a false assurance of safety, the strategies themselves can actually increase vulnerability and risk.

Erroneous / Unreliable strategy #1: (See Poster)
Erroneous / unreliable strategy #2:
    This unreliable strategy suggests that you
    • stand at the curb until a perpendicular vehicle passes.
    • wait until that vehicle has receded for a period of time that is as long as you need to cross.
    • If you don't hear any approaching vehicles during that time, you can conclude that it is clear enough to allow you time to cross.
    For example, suppose you need 6 second to cross. Whenever a perpendicular vehicle passes you and you can count 6 seconds without hearing any approaching traffic, this unreliable strategy assumes that you have enough time to cross before any car will reach you.

    two photos show Paul and Jomania standing at the straight street with stopwatches as cars approach from the right and left. two photos show Paul and Jomania standing at the straight street with stopwatches as cars approach from the right and left.

    The erroneous assumption with this strategy is that the time it takes for a car to recede from you is at least as long as the time it takes for an approaching car to reach you, once you hear it over the sound of the receding car. This assumption is NOT valid.

    Assumption behind the strategy:
      This strategy assumes that receding vehicles
    • will not significantly mask the sound of approaching cars
    • will not be louder or faster than the approaching cars, so that the approaching vehicle, once it is heard above the sound of the receding car, will take at least as long to reach you as the first vehicle had taken to recede from you.

    Experimental analysis of the theory:
      Testing at three busy rural and suburban two-lane streets reveals this assumption to be false. At each street, I used a stopwatch to measure the time from when a perpendicular vehicle passed in front of me until I heard an approaching vehicle, then measured the time until that approaching car reached me.

      Results:
        Almost half the approaching vehicles reached me in less time that the passing vehicle's receding time, sometimes by as much as 60% less than the time that the first car had receded (see Table 2 below).

    MYTH BUSTED - this strategy is based on a false assumption and if it is used, it could actually increase the risk because the sound of vehicles approaching your crossing are masked by the sound of the vehicles receding from you.

      Table 2. The time of receding cars from when they passed the experimenter until an approaching car was heard is compared with the time from when the approaching car was heard until it reached the experimenter. A negative difference indicates that the time for the approaching car was less than that of the receding car (the difference is then shown as a percent of the receding car's time).

      Busy rural two-lane street table test
      time of receding vehicles (secs)
      time of approaching vehicles (secs)
      difference (inc. % of receding vehicle's time)
      7.6
      4.8
      -2.8 (37%)
      4.4
      3.2
      -1.2 (27%)
      4.0
      6.8
      +2.8
      4.4
      4.6
      +.2
      7.1
      4.3
      -2.8 (39%)
      9.4
      7.5
      -1.9 (20%)
      6.3
      3.5
      -2.8 (44%)
      12.2
      13.0
      + .8
      4.0
      4.8
      + .8
      13.6
      9.5
      -4.1 (30%)
      23.4
      14.6
      -8.8 (38%)
      10.0
      6.9
      -3.1 (31%)
      5.5
      8.3
      +2.8
      5.5
      8.2
      +2.7


      Busy residential two-lane street table test
      time of receding vehicles (secs)
      time of approaching vehicles (secs)
      difference (inc. % of receding vehicle's time)
      3.7
      4.2
      + .5
      9.3
      11.0
      +1.7
      10.3
      11.1
      + .8
      4.4
      5.7
      +1.3
      6.6
      10.8
      +4.2
      4.5
      3.8
      - .7 (16%)
      2.0
      3.8
      +1.8
      11.8
      12.4
      + .6
      4.7
      6.0
      +1.3
      4.2
      14.1
      +9.9
      7.1
      7.8
      +0.7
      3.7
      10.0
      +6.3
      9.4
      9.7
      + .3
      7.6
      13.0
      +5.4


      Busy suburban two-lane street table test
      time of receding vehicles (secs)
      time of approaching vehicles (secs)
      difference (inc. % of receding vehicle's time)
      11.8
      4.7
      -7.1 (60%)
      5.7
      5.5
      -0.2 (4%)
      11.0
      10.9
      -0.1 (<1%)
      5.9
      3.2
      -2.7 (46%)
      3.4
      1.1
      -2.3 (68%)
      6.3
      3.0
      -3.3 (52%)
      5.7
      3.5
      -2.2 (39%)
      3.4
      2.4
      -1.0 (29%)


Wall Emerson, R. & Sauerburger, D (2008). "Detecting approaching vehicles at streets with no traffic control." Journal of Visual Impairment and Blindness, AFB Press, Volume 102, Number 12, pp. 747-760

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