Re: Monitor traffic speed

[Mark Sylvester <msylvest@SPIN.IT>]

At 02:16 PM 7/10/00 -0400, Owen von Kugelgen wrote:
> A student wants to monitor speed of cars on her street while she's at school.
>  Has anyone on the list tried something like this?  Suggestions for a simple
> experimental set up would be appreciated.  The student would ideally like to
> use a CBL, LabPro or Pasco interface and use a computer to efficiently
> calculate speeds from the data collected.
>
> Simplest  idea so far (but labor intensive):
> - Videotape the street from her window, using trees or lines on the street to
> indicate distance.  Then measure speed by (dist per frame)/(frame rate) or
> use VideoPoint software).


We had a traffic speed survey near different school buildings as part of a
project a couple of years back, and the video camera method you describe is
what we used. Yes it is labour intensive, but by far the simplest hardware
setup, especially for public streets. The Pasco ultrasonic sensor will not
work at the distances involved here. If you could set up two light gates
that could do the job, but one would not want to leave the setup unattended.

Pedagogically, the videotape method has some advantages. I can think of (i)
a calculation to eliminate parallax based to the lens angle and the
relevant distances and (ii) use of an appropriate sampling method to avoid
having to measure the speed of every vehicle.

good luck!

Mark

Mark Sylvester
United World College of the Adriatic
Duino, TS
Italy.