Newlands Cross Upgrade EIS - European Investment Bank

South Dublin County Council N7 Newlands Cross Upgrade
Environmental Impact Statement
Arup Consulting Engineers
be an entry point at the most western point of the works with an exit just before Newlands
Cross Junction.
The second entry point will be the other side of the junction with an exit close to the most
easterly point of the works. There will be a similiar arrangement for traffic coming from
Dublin travelling westbound i.e. the first entry close to the most easterly point of the works,
exiting in advance of the junction and the second entry just beyond the junction, exiting at the
western most point of the works.
3.7.5 Traffic Management during Construction
A number of traffic management measures will be implemented during the phasing of
construction works for both options as follows.
3.7.5.1 Option 1 – Overpass
Temporary traffic diversions will be constructed offline and to the south of the proposed
overbridge location to facilitate the diversion of the Naas Road (N7) from its current
alignment while existing traffic flow is maintained. Temporary traffic lights, barriers and road
markings will also be put in place. All existing traffic movements will be accommodated
within the temporary traffic phasing.
There will be a number of overnight closures when the precast beams are being lifted into
place. These closures will occur to the east and west spans of the bridge deck. Traffic,
pedestrian and cycle movement through the junction will be facilitated during this period.
Once constructed all mainline N7 traffic will be diverted onto the overbridge structure. The
temporary diversions will be removed and final highway arrangements for the merge and
diverge lanes will be constructed in stages to facilitate relevant left, right and through turning
movements. Left, right and through turning movements will also be accommodated while
remaining upgrade works are carried out on the Fonthill / Belgard Road (R113).
Traffic management during construction is depicted on Figure 3.5a and 3.5b.
3.7.5.2 Option 2 – Underpass
Initially, traffic flow will be maintained through the junction as per the existing layout while
offline works such as temporary traffic barriers, site compounds, temporary road diversions
for eastbound and westbound carriageways and utilities, road markings and temporary traffic
lights are put in place.
While the underpass is being constructed mainline traffic will be diverted to the north and
south of the proposed N7 mainline. The Fonthill / Belgard Road (R113) traffic will be
diverted through the junction using a contraflow system. The traffic will be diverted in two
stages to facilitate construction of the bridge in two halves. Once the eastern half of the bridge
deck carrying the Fonthill / Belgard Road (R113) over the N7 mainline is complete then the
Fonthill / Belgard Road (R113) traffic will be diverted onto that portion of the completed
bridge in order that the western half of the bridge can be constructed.
Once the bridge deck is complete the contraflow system on the Fonthill / Belgard Road
(R113) will be removed. The traffic will also be diverted back onto the Naas Road (N7)
following completion of the re-alignment. The temporary diversions will be removed and
final highway arrangements for the merge and diverge lanes will be constructed in stages to
facilitate relevant left, right and through turning movements. Left, right and through turning
movements will also be accommodated while remaining upgrade works are carried out on the
Fonthill / Belgard Road (R113).
Traffic management for the N7 mainline during construction of the Underpass is depicted on
Figure 3.5c, 3.5d, 3.5e and 3.5f.
December 2007 Page 23