Conversion Challenge

[tazdevil]

Done it, divide the given headway by the average speed converted to metres/sec, so 678 / (63.88 * 1000 / 3600) gives 38.2 I can now usurp the service I've reverse engineered

OK I'm having to do some reverse engineering and have a problem coming up with a conversion. The subject is traffic detectors and the raw data is below. Somehow the figures need to be converted to produce the following:

Occupancy - 0 - straight from the Occupancy field.
Speed - 63.86 - the average speed taking all vehicles into account
Flow - 7 - simply the total of vehicles.
Headway - 38.22 - ???

So can anyone take the figures below and tell me how to compute a headway of 38.22 from them

    <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" />
          <Class ClassNr="3"
                 NumVeh="0"
                 Speed="0"
                 GapTime="0" />
        </Zone>
      </Body>
    </Message>

 

[northernladuk]

Depends

Have you asked on the IPSE forum?

 

[tazdevil]

Depends

on what

 

[northernladuk]

on what

stuff

 

[tazdevil]

Depends

Have you asked on the IPSE forum?

Nope, cos I'm not a member any more and £200+ to browse forums is a bit steep

 

[The Castle Cary Fairy]

Maybe a definition of what exactly headway is may provide some pointers?

[/Headway is a measurement of the distance or time between vehicles in a transit system. The minimum headway is the shortest such distance or time achievable by a system without a reduction in the speed of vehicles.

 

[WTFH]

Depends

Have you asked on the IPSE forum?

Shirely you mean the IRSE forum? (although that's about train tracks, not roads)

 

[Uncle Albert]

Maybe a definition of what exactly headway is may provide some pointers?

The concept of level of service in highway traffic flow illustrates the differences in the characteristics of the flow which may be examined by a study of the headways between vehicles. Time headways are the time intervals between the passage of successive vehicles past a point on the highway. Because the inverse of the mean time headway is the rate of flow, headways have been described as the fundamental building blocks of traffic flow. When the traffic flow reaches its maximum value then the time headway reaches its minimum value.

HTH BIDI

 

[NotAllThere]

Do you have any more data points?

 

[WTFH]

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