Conversion Challenge

**scooterscot** · 27 April 2018, 13:28

I assume 'headway' means: a measurement of the distance or time between vehicles in a transit system.

Seems to be a solution for Poisson for sure, can I be bothered understanding what the coefficients are..

**tazdevil** · 27 April 2018, 14:11

Originally posted by WTFH View Post

Are the 3 classes actually 3 lanes on the road, or 3 types of vehicle?

Three classes of vehicle being small (bikes), medium (cars) and large (trucks).

**tazdevil** · 27 April 2018, 14:17

Originally posted by NotAllThere View Post

Do you have any more data points?

Yup lots more courtesy of wireshark but will it help? Another example below which produces a headway figure of 21.36. Whether the headway is time or space I'm not sure but some bright person around here should be able to suss it?

Code:

    <Message Type="Data">
      <Body Type="IntegratedData"
            IntervalTime="300"
            DataNumber="765"
            Utc="1524800400"
            MilliSeconds="19">
        <Zone ZoneId="1"
              Occupancy="1"
              Confidence="8"
              Length="32"
              HeadWay="376"
              Density="3">
          <Class ClassNr="1"
                 NumVeh="6"
                 Speed="62"
                 GapTime="236" />
          <Class ClassNr="2"
                 NumVeh="7"
                 Speed="65"
                 GapTime="218" />
          <Class ClassNr="3"
                 NumVeh="1"
                 Speed="60"
                 GapTime="130" />
        </Zone>
      </Body>
    </Message>

**WTFH** · 27 April 2018, 14:20

Originally posted by tazdevil View Post

Three classes of vehicle being small (bikes), medium (cars) and large (trucks).

Then some of your data (or the data units) don't make sense.

Code:

    <Message Type="Data">
      <Body Type="IntegratedData"
            IntervalTime="300"          - seconds
            DataNumber="759"
            Utc="1524800100"           - seconds since 1/1/1970
            MilliSeconds="27">
        <Zone ZoneId="1"
              Occupancy="0"
              Confidence="8"
              Length="27"
              HeadWay="678"
              Density="1">
          <Class ClassNr="1"
                 NumVeh="5"
                 Speed="63"
                 GapTime="400" />
          <Class ClassNr="2"
                 NumVeh="2"
                 Speed="66"
                 GapTime="408" />
        </Zone>
      </Body>
    </Message>

If the data is 300 seconds worth, then the GapTime cannot be 400 seconds.

If the gap time is 400 milliseconds, that means the vehicles are approx 7 metres apart at 63km/h. Not 7m from rear bumper of one to front of the next, but from front of one to front of the next. For a 6m long truck, that would mean there's 1m between it and the next one.
That's kinda beyond dangerously close.

**WTFH** · 27 April 2018, 14:29

OK, can you find a piece of data where you have the headway and there's only 1 class of vehicle?

**tazdevil** · 27 April 2018, 15:34

Sorted, see initial post

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