Newlands Cross Upgrade EIS - European Investment Bank

South Dublin County Council N7 Newlands Cross Upgrade
Environmental Impact Statement
Arup Consulting Engineers
On a local level, the proposed upgrading of the Newlands Cross Junction is a specific
objective (No. 52) of the South Dublin County Development Plan 2004 – 2010.
NTS3. BACKGROUND TO THE PROJECT/ALTERNATIVES
Once the Red Cow Interchange has its upgrade completed as part of the M50 Widening,
Newlands Cross will pose a significant constraint on what is a major national road upgraded
to a high quality. With this in mind South Dublin County Council and the NRA propose to
address this constraint at Newlands Cross. This project will represent a major positive impact
on the policies of the National Development Plan 2007-2013, Transport 21 and other policies.
The Naas Road is a primary transportation corridor servicing the area. In addition, the N7
National Primary Route has been identified in the National Spatial Strategy as a
Transportation Corridor linking the Metropolitan areas of the Greater Dublin and Mid-East
Regions with the Metropolitan areas of Limerick and Cork. Since March 2003, the R110 east
of the M50 Red Cow Interchange has become a Strategic Route and as such is managed by the
Dublin Region Traffic Management Centre, as agreed by the four Dublin Local Authorities. It
is proposed to add the section of the N7 from Red Cow to Newland Cross to the Strategic
Route at a later date.
Newlands Cross is located in the suburb of Clondalkin with a diverse mixed use urban setting
which includes an array of residential, retail, community, agricultural and amenity land uses.
The ‘Do-Minimum’ Option assumes that the Newlands Cross Interchange is not upgraded to a
grade separated junction i.e. that the existing N7 Mainline and Belgard / Fonthill Road (R113)
would remain at the level at which they are currently. The ‘Do-Minimum’ Option is likely to
lead to increasingly significant pressure on the existing road and regional road network and
would limit the development capacity of the local area.
An initial feasibility study examined at grade and grade separated options for an upgrade of
the junction and concluded that grade separation was required. Some initial conclusions were
also reached on the format of the junction that would be provided within the grade separation
scheme.
A further assessment was undertaken in relation to the alignment options for grade separation.
This was carried out under the following three headings in order to narrow down the number
of options for further assessment:
a) Mainline Road: A review was carried out to assess whether the N7 or the R113 should be
the mainline. It was decided that the N7 should be the mainline based on its importance as
a National Primary Road.
b) Vertical Alignment: A review was carried out to assess vertical alignment options.
Overpass, underpass and half and half options were examined. On the basis of the review
undertaken it was decided to discount half and half and continue with overpass and
underpass
c) Horizontal Alignment: A review was undertaken to assess horizontal alignment options.
The constraints identified above ruled out a large scale realignment of the N7 and also
steered the scheme towards land take to the south of the existing public road corridor.
This process concluded that a grade separation of the N7 mainline from the remainder of the
junction was a feasible junction layout. This layout could be progressed as either an underpass
or an overpass. Further assessment of both options was then carried out to minimise land take
and analysis was undertaken to validate these scheme design refinements. The assessment was
carried out under a number of criteria (i.e. Construction, environmental, economic etc.) to
enable the full consideration of the likely effects of each option.
December 2007 Page NTS2