2.1.1
The Project involves widening
the following sections of TMR from dual-two carriageway to dual-three
carriageway:-
•
Wong Chu Road Section, (from Wong Chu Road Interchange to Tuen Hing Road);
and
•
Tuen Mun Town Plaza Section, (from Tuen Hing Road to Yan Oi Town Square).
2.2.1
Tuen Mun Road Town Centre
section is a primary distributor
with high capacity junction. The study area is generally a populated area
dominated by high-rise buildings.
2.2.2
As stated in the EIA Study
Brief, the boundary of the assessment area for this EIA should be 500m from
either side of and along the full stretch of the proposed road alignment,
except that, for noise and water quality impact assessments, the study area
should be defined by a distance of 300m from the proposed road alignment. As for LVIA, according to EIA Study
Brief No. ESB-161/2006, the study area for the landscape impact assessment
shall include all areas within 100m extended from the boundary of the scope of
the EIA study.
2.2.3
For noise impact assessment,
the study area could be reduced accordingly if the first layer of the noise
sensitive receivers (NSRs) is closer than 300m
from the road and provide acoustic shielding to those receivers at further
distance behind subject to agreement of the Director of Environmental
Protection.
2.2.4
With regard to the visual
impact assessment, all sensitive receivers should be assessed within the visual
envelope outlining the area of land.
The assessment should include the view on any part of the proposed road
and the associated structures.
2.3.1
TMRTCS
is currently operating close to its capacity. In the morning peak period (7a.m. – 9a.m.), the volume/capacity (v/c) ratios of the
southbound two-lane carriageways are in the range of 0.89 – 0.99. In other words, TMRTCS at these two-lane
sections is operating close to its design capacity and there is little spare
capacity to cater for future traffic growth.
2.3.2
The
objective of the Assignment is to propose improvement measures to resolve the
traffic congestion problem of TMRTCS.
The traffic improvement option developed under the Feasibility Stage
were compared and evaluated and bring forward in this Assignment for the
detailed design and construction.
2.3.3
Without the Project, TMRTCS roads will operate to its
design capacity and will be severely affected as it becomes a bottleneck due to
increased traffic from HK-SWC and growth in the territory. Congestions and queues would be resulted
along this section of the road and it would finally adverse the HK-SWC traffic
as well as Tuen Mun residents.
2.3.4
The scope of the Project
comprises:
a)
Widening of the Tuen Mun Road Town Centre Section
between Yan Oi Town Square to Wong Chu
Road with one additional traffic lane for both Kowloon bound
and Yuen Long bound carriageways;
b)
Construction of a one-lane flyover to connect Tsing
Hoi Circuit and Tuen Mun Road
Kowloon bound carriageway;
c)
Improvement of existing traffic light
signal-controlled junctions along Castle
Peak Road;
d)
Re-provision of four numbers of existing
footbridges;
e)
Installation of cantilever/vertical noise barriers
and noise enclosures; and
f)
Associated works including slope, drainage,
landscaping, water and utility works; installation of traffic control &
surveillance systems; and modification of directional signs.
2.4.1
For the Feasibility Study under
the HyD Agreement No. CE 38/2005(HY), four options have been considered for
traffic improvement
of Tuen Mun Road Town Centre Section.
The four options include:
Ÿ
Option 1 – Sam
Shing Hui Slip Road Option: This option suggested
a new interchange constructed at Sam Shing Hui
Ÿ
Option 2 – Tunnel Option: This scheme was initiated by TMDC
members during consultations
Ÿ
Option 3 – Dual 3-lane Widening Option which is currently
adopted
Ÿ
Option 4 – Dual 3-lane Widening combined with modified slip
road option
2.4.2
An Option Assessment Report was
completed under Agreement No. CE 38/2005 (HY) and the recommendations were
brought forward to this Investigation, Design and Construction Assignment. The above four traffic improvement
options were compared and evaluated against the criteria including traffic
benefits, social benefits, engineering feasibility, environmental impacts, land
requirements, programme and costs.
2.4.3
Having assessed and evaluated
each of these options, the D3 Option was selected as the preferred option of the
Project. The recommended option was presented to the Tuen Mun District Council
(TMDC) on 10 November 2006. The TMDC had no objection to the implementation of
the recommended option and reiterated the urgency of the Project.
2.4.4
The text below summarizes the
key findings of each option.
Option
1 (Sam Shing Hui Slip Road
Option)
2.4.5
This option involves building
an additional interchange consisting of two new slip roads to connect Tuen Mun Road and
Castle Peak Road (CPR) near Sam Shing Estate to alleviate the traffic problem
of TMRTCS. The layout is shown in Figure 2.1. The scheme is to attract
traffic used to travel along TMRTCS to use CPR. The traffic diversion would
inevitably increase the traffic flows along CPR and the performance of the
junctions along CPR would be adversely affected. As such, it is necessary to implement
the junction modification to mitigate the effect on CPR junctions. The scheme
would bring benefits to relieve the TMR traffic. However, the actual
performance of the scheme is subject the actual driver behaviour or decisions
on choosing CPR instead of TMR.
2.4.6
The Tuen Mun District Council (TMDC)
Traffic and Transport Committee (T&TC) were consulted on the Additional
Interchange Scheme on 13 May 2005 and 29 June 2005. However, the DC Members and local
residents strongly objected to this option. They alleged that the proposed
additional interchange could not possibly solve the traffic problems in the
TMRTCS. More importantly, they
claimed that the additional interchange would adversely affect their
environment and might probably degrade the value of their properties nearby.
2.4.7
The option incurred the lowest
capital cost and recurrent cost. The traffic benefit is comparable to the
recommended option (Option 3 – D3 Widening Option). However, due to the strong
objection from the public, this option is not recommended.
Option 2: (Tunnel Option)
2.4.8
The tunnel option was initiated
by Tuen Mun DC members. An optimal scheme for the tunnel option
as shown in Figure 2.2 & 2.3.
The tunnel running between Tsing Yung Terrace and Tsing Tin Interchange
would need to be constructed by cut and cover method in view of the topographic
condition and the shallow depth requirements to allow connection to the
existing highway. This option was considered not feasible as the tunnel
excavation and construction works will require closure of existing traffic
lanes at TMRTCS. TMR is a sensitive
“Red” route on which lane closure is prohibited during peak hours under normal
circumstance. Construction of the proposed tunnel would take several years. It
is necessary to implement substantial temporary traffic measure to divert
traffic to the adjacent local road networks at the town centre. However, traffic diversion is not
practicable in view of capacity of local road and the junctions. Therefore,
this option is considered not feasible and not recommended.
Option 3: (Dual 3-lane Widening Option which is currently adopted)
2.4.9
Under this option, the existing
dual 2-lane carriageway of TMRTCS will be widened to a dual 3-lane highway. The
traffic directly benefits from the road widening without the traffic diversion
as required in Option 1. It is noted the traffic performance of the tunnel
option would be better than this option as the tunnel option which provides an
extra 2 lanes on each direction. However, the construction of tunnel would
require closure of Tuen Mun Road Town Centre Section for years while this
option would be able to maintain the existing traffic. This is of paramount
importance to keep Tuen Mun Road
live since it serves as one of the key linkages to the North West New
Territories.
2.4.10 As the works under this option involves substantial widening of
existing distributor road, the Project will be classified as a Designated
Project and require full compliance to various regulations as stipulated in EIA
Ordinance. As a result, the road
widening works will be associated with a very extensive noise barrier and noise
enclosure along TMRTCS. The
construction of noise enclosure would impose substantial persisting visual
impact to the adjacent VSRs. However, on the other hand, it is an opportunity
to address the public request for mitigating the noise nuisance created by
TMRTCS traffic. This is in fact one
of the key concerns within the Tuen Mun District.
Option 4: (Dual 3-lane Widening combined with modified slip road
option)
2.4.11 It is a combined scheme of Option 1 and Option 3. It involves
upgrading of existing dual 2-lane carriageway of TMRTCS to dual 3-lane
carriageway and construction of additional interchange near Sam Shing Estate.
Although the layout of the new slip roads is different from Option 1 as shown
in Figure 2.4, it is expected strong objection will be received from the
public with the reasons similar to that for Option 1. Hence, Option 4 was not selected.
Recent Consultations and Recent Developments
2.4.12 The D3 option was presented to the TMDC T&TC on 10 November 2006
and was well-received by TMDC. A number of consultations to TMDC and site
meetings with District Facilities Management Committee (DFMC) members of TMDC have
also been carried out on various aspects of the Project, including roadworks,
trees, noise barriers/enclosures, greening designs of noise
barriers/enclosures. The following table summarises the consultation meetings.
|
Date
|
Subject
|
|
14/9/2007
|
|
|
21/9/2007
|
|
|
19/2/2008
|
|
|
14/3/2008
|
|
|
29/4/2008
|
|
|
15/5/2008
|
|
|
28/5/2008
|
|
|
21/11/2008
|
|
2.4.13
Recently, the Final Report for
the Tuen Mun - Chek Lap Kok Link and Tuen Mun Western Bypass – Feasibility
Study under CE 28/2005 (HY) indicates that even with both the Tuen Mun Western
Bypass and TMRTCS widening works in place in 2021, the critical section of
TMRTCS is also predicted to operate over its design capacity with v/c ratio =
1.02 during the critical AM peak hour. Thus the widening works along TMRTCS is necessary
to relieve the traffic congestions.
2.5.1
The widening of the approximate 1.5km long at-grade road is a very complicated construction
process that warrant careful planning on the construction sequences and
activities. For the purpose of this
EIA Study, two alternative construction methods are derived and evaluated as following:
(a)
Widening and re-construction by partly closing existing
lanes of Tuen Mun Road:
The advantage of this construction method is that a shorter
construction period can be achieved thus resulting construction impacts of
shorter term. However, there are
very significant drawbacks as described follows:
·
Higher impacts on noise and air quality during construction
period;
·
Reduce existing carrying capacities of Tuen Mun Road;
·
Result in frequent congestions; and
·
Disturbance to existing road users and Tuen Mun residents;
(b)
Widening and re-construction of Tuen Mun Road in stages without affecting
the current lane arrangements:
Under this option, the concerned section of Tuen Mun Road will
be widened and re-constructed in stages involving multi-construction stages and
temporary traffic arrangement (TTA).
Though the construction period will be longer, the following advantages
can be achieved:
·
Existing carrying capacities of Tuen Mun Road can be maintained;
·
Less noise and air quality impacts during construction
period thus more manageable; and
·
Less disturbance to existing road users and Tuen Mun
residents, in terms of traffic.
2.5.2
To conclude, as the current Tuen Mun Road is a major trunk road
linking between Tune Mun and Kowloon/
Tsuen Wan, closing any part of existing lanes would result in reduction of the
current carrying capacities of TMR thus having a huge adverse impact to both
the traffic and the Tuen Mun residents. Despite the advantages that option (a)
offered, maintaining the existing carrying capacities would be a prerequisite
requirement of the Project and the drawbacks under option (b) are manageable
and acceptable. Therefore, it is considered that option (b) should be adopted.
2.6.1
The construction of the Project is originally planned
to commence in late 2008 for completion by 2010. Due to a number of factors and
various design developments, the commencement of the Project is postponed and
the completion date will be delayed to 2012.
2.6.2
As a result from the change of completion date to
2012, a review on the traffic figures adopted in this assessment has been
carried out. The 2025 traffic forecast endorsed by TD for use in this
assessment was derived from the 2003-based TPEDM SI planning data. However,
this set of planning data is now superseded by the 2006-based TPEDM SI planning
data which was released by PlanD in mid 2008. Comparing the 2027 population and
employment data in NWNT from the 2006-based TPEDM SI against the assumed 2025
population and employment data adopted in the 2025 traffic forecast, the 2027
figures obtained from the 2006-based TPEDM SI planning data are even smaller
than the assumed 2025 figures adopted in the 2025 traffic forecast which were
developed with reference to the 2003-based TPEDM SI planning data. There are
some reductions in population and employment assumptions in the 2006-based
TPEDM SI planning data. Since the traffic flows on TMRTCS are in proportion to
the population and employment of NWNT (i.e. Tuen Mun/Tin Shui Wai/Yuen Long
areas), the endorsed 2025 traffic forecast for the EIA are derived from a set
of relatively higher population and employment assumptions. Hence even the
assessment year of the EIA is postponed to 2027 and the traffic forecast for
the EIA is to be updated with the latest set of 2006-based TPEDM SI planning
data, the 2027 traffic forecast so produced would still be anticipated to be less
than the endorsed 2025 traffic forecast. Therefore, the current traffic data
adopted represents a critical situation.
2.6.3
The preliminary construction programme of the Project
is shown on Appendix 3.5.
2.7.1
The Project would have interface with the following
projects:
·
Widening of Tuen
Mun Road at Tsing Tin Interchange under Contract
No. HY/2007/14;
·
Reconstruction and Improvement of Tuen Mun Road – Sam Shing Hui Section
under Contract No. HY/2008/11;
The site boundaries
of the above projects are located within 500m study area of this Project and their construction
periods would overlap with this Project. The construction for Contract No.
HY/2007/14 commenced in June 2008 for completion in 2010 whereas Contract No. HY/2008/11
is scheduled to commence in mid 2009 for completion in mid 2014. The location of concurrent projects
within 500m of the
study area is indicated in Figure 1.1.