Newlands Cross Upgrade EIS - European Investment Bank

South Dublin County Council Newlands Cross Grade Separation
Traffic Modelling: Working Paper No. 1
2. MODEL DEVELOPMENT
2.1 Modelling Approach and Preliminary Work
SATURN is used by the DTO in their AM Strategic model. A SATURN model covering the
study area in detail was produced by Arup on behalf of SDCC for the assessment of the
proposed Dublin Outer Ring Road. SATURN therefore represented a cost-effective platform
to be used to carry out traffic assessment of the Newlands Cross Improvements. SATURN
allows detailed modelling of delays at junctions whilst also showing the wider network
implications of the proposals. A local SATURN model, based on the DTO’s Dublin Strategic
Model and complemented by information from the ORR mode, was therefore developed for
this project.
Arup met with the Dublin Transportation Office (DTO) on Friday 9 September and
Wednesday 2 November 2005. The meetings had the following objectives:
• Introduce the Newlands Cross study to the DTO Research and Planning team;
• Obtain general information about the DTO strategic model;
• Discuss the information and modelling work that Arup would require from the
DTO and obtain an estimate of the cost and duration of these works;
• Discussion of Arup’s modelling proposals regarding network, scenarios,
assessment years, growth, etc; and.
The proposed modelling methodology outlined in the sections below is based on the
discussions with SDCC and the DTO.
2.1.1 Traffic Assessment Years
Arup was advised by the DTO that the existing 2002 strategic model validated to 2002 and
updated to include strategic network improvements up to 2005 would form the basis of the
cordon model. Recalibration and validation of the local model to 2005 traffic conditions will
be undertaken by Arup.
The opening and design years of 2009 and 2024 were used in the assessment (although the
output data was subsequently extrapolated to 2010 ands 2025.
2.1.2 Traffic Assessment Periods
The model represents the AM peak hour (08:00 to 09:00).
2.1.3 Network and Matrices
Based on preliminary SATURN assessment results using the ORR model, the proposed
simulation network spans between the N4 and the N81 from north to south and between the
R112 and the County Kildare boundary from east to west.
The traffic model network and matrices were obtained from the DTO’s Dublin SATURN AM
peak model by cordoning the selected study area. The DTO will provide information for the
07:00 to 08:00 and 08:00 to 09:00 periods. Information from the 07:00 to 08:00 period will be
loaded into the local model to reflect traffic conditions prior to the peak hour.
2.1.4 Existing Situation
Model Network Audit
A review of the DTO network (nodes, links and zoning) and comprehensive site visits were
undertaken to obtain additional information on geometry and operation of key links and
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REPORT_FINAL REV1.DOC
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Final 3 November 2005