07/2398 - Request for information response [As Published] · 132007.2398

 

 

Council has also requested validation of the traffic model.

It is important to note that SIDRA 3.2 is an analytical software package. Validation of transport
models is generally applicable to simulation model (eg. VISSIM, Paramics) and strategic
predictive models (eg VISUM, EMME/2). Validation is not generally applied to an analytical
software package, however consideration has been given to testing the input parameters to
determine if this makes any difference to the assessment. The following is a discussion on the
input parameter critical to the analytical analysis - gap acceptance.

2.1 Gap Acceptance Parameters

The assessment in the initial traffic report (Ref 1) adopted the following critical gap
acceptance (t.) and follow-up headway (t) parameters:

N MRC adopted Gap Acceptance Parameters for two-way / two-lane roads

® — Right-turn from Diamond Road - t= §.5s
, - t =3.0s ,
= Left-turn from Diamond Road - t=4.5s
- t =2.5s
* — Right-turn from Elm Street across one-lane—- ta = 4.0s
- t =2.0s _
These parameters — RRREE R  m

NM Are based on over 20 years of assessment undertaken by MRC and has been
accepted by the Planning and Environment Court in numerous appeals; and

Are similar to those provided within the Department of Main Roads’ (DMR)
“Road Planning and Design Manual”, although it is noted that the DMR
parameters would produce slightly modified results at the Diamond Street
approach as the critical gap (t,) in DMR’s manual is 5s for the right-tum
movement, which is less than the critical gap adopted in the initial assessment,
and 5s for the left-turn movement, which is higher than the critical gap adopted
in the initial assessment.

The DMR parameters are listed below:

DMR Gap Acceptance Parameters for two-way / two-lane roads

 

* — Right-turn from Diamond Road . - t = 5.0s
. : - t =3.0s
s — Left-turn from Diamond Road - t = 5.0s
- tr = 2.0-3.0s (~2.5s)
= Right-turn from Elm Street across one-lane-- t = 4.0s “
- t =2.0s

     

wrerw.mreagney.com cofsuttants in transportation
3427-002{1) - RFI.doc