Newlands Cross Upgrade EIS - European Investment Bank

South Dublin County Council N7 Newlands Cross Upgrade
Environmental Impact Statement
3.8 Planning Constraints
Arup Consulting Engineers
The Newlands Cross junction is within the administrative area of South Dublin County
Council. Therefore the upgrade works are subject to the requirements of the South Dublin
County Council, County Development Plan 2004 – 2010.
Specific Local Objective No. 52 of this plan specifies the following with regard to the upgrade
of Newlands Cross:
"Construct a grade-separated junction at Newlands Cross, to include an
appropriate local traffic and segregated pedestrian facility at ground level with
the N7 through traffic below grade."
To facilitate consideration of alternative options for the junction, the following variation was
made to the Development Plan on 12 th November 2007:
“Construct a grade-separated junction at Newlands Cross and that this
Council favours an underpass on the N7 at Newlands Cross on the
grounds that it may have less environmental impact than an overpass.”
3.9 Noise and Vibration
AWN Consulting were commissioned by Arup Consulting Engineers to carry out a desk-study
addressing the noise and vibration impacts for the various options of the proposed
development. The findings of their report is outlined in the following sections:
3.9.1 Executive Summary
This report assesses and compares the Noise and Vibration impact associated with the two
options for the construction and operational phases of the proposed Newlands Cross upgrade.
This noise assessments follow the standard practice of adopting the traffic noise design goal
contained within the National Roads Authority (NRA) guidance document entitled Guidelines
for the Treatment of Noise and Vibration in National Road Schemes 1 .
The operational noise impact associated with the overpass option will result in mitigation
being required at five of the twenty-five receivers assessed. Mitigation measures have been
specified such that the predicted Do Something levels are less then or equal to the predicted
Do Nothing levels. The degree of impact associated with the overpass option is ‘neutral’.
The operational noise impact associated with the Underpass option will result in mitigation
being required at none of the twenty-five receivers assessed. The predicted Do Something
levels are less then or equal to the predicted Do Nothing levels. The degree of impact
associated with the underpass option is ‘neutral to slightly positive’.
Note that the use of a low noise surface, that will offer a minimum of a 3.5dB reduction
compared to hot rolled asphalt, has been assumed in both scenarios.
In respect of construction noise, the noise level limits set out in the NRA Guidelines are
adopted. Regardless of the final choice of the road configuration, mitigation measures will be
necessary to limit construction noise levels to these values. However it is noted that
construction programme for the Underpass option will involve more sources of vibration (i.e.
increased rock-breaking) than the Overpass option.
December 2007 Page 24