PWSC(97-98)116
For discussion
on 11 February 1998


ITEM FOR PUBLIC WORKS
SUBCOMMITTEE OF FINANCE COMMITTEE

HEAD 711 - HOUSING
Transport - Roads
578TH - Wong Chuk Hang Road flyover and associated road widening

Members are invited to recommend to Finance Committee the upgrading of 578TH to Category A at an estimated cost of $305.8 million in money-of-the-day prices for the construction of the Wong Chuk Hang Road flyover and associated road widening.

PROBLEM

The junction capacity of Wong Chuk Hang Road/Nam Long Shan Road will be unable to cope with the future traffic demand arising from the developments in Ap Lei Chau, Aberdeen and Wong Chuk Hang.

PROPOSAL

2. The Director of Highways, with the support of the Secretary for Housing and the Secretary for Transport, proposes to upgrade 578TH to Category A at an estimated cost of $305.8 million in money-of-the-day (MOD) prices for the construction of a dual 2-lane flyover along Wong Chuk Hang Road over its junction with Nam Long Shan Road and associated road widening works.

PROJECT SCOPE AND NATURE

3. The scope of the project comprises -

  1. construction of a 550-metre-long dual 2-lane flyover along Wong Chuk Hang Road over its junction with Nam Long Shan Road;

  2. associated widening and reconstruction of a 660-metre-long section of Wong Chuk Hang Road;

  3. demolition of a footbridge across Wong Chuk Hang Road at its junction with Nam Long Shan Road; and

  4. ancillary traffic aids, drainage and landscape works.

JUSTIFICATION

4. Wong Chuk Hang Road is a primary distributor in the Southern District. It serves as part of Route 1 linking various areas of Wong Chuk Hang, Aberdeen, Ap Lei Chau, Tin Wan and Pok Fu Lam to Wan Chai.

5. With the gradual completion of developments including several planned housing sites in Wong Chuk Hang, Ap Lei Chau and Aberdeen, we expect that the traffic volume at the signalised junction of Wong Chuk Hang Road and Nam Long Shan Road will increase significantly. We estimate that without the proposed flyover, the signalised junction will be overloaded by 2002 and severe congestion will occur by 2004 leading to a gridlock situation in the local road network.

6. We have investigated the use of Heung Yip Road and Ocean Park Road as the alternative routes to relieve the anticipated traffic congestion at the signalised junction without the proposed flyover. Such an alternative proposal is considered impracticable and unacceptable from traffic engineering point of view due to inadequate weaving length at critical road junctions. Furthermore, the additional diverted traffic from Nam Long Shan Road to Heung Yip Road and Ocean Park Road will create capacity problems and safety concerns. A more detailed description of the traffic assessment is at Enclosure 1.

6. The proposed Wong Chuk Hang Road flyover will allow uninterrupted flow for east-west traffic movements, thus improving the junction capacity at Nam Long Shan Road and Wong Chuk Hang Road. Together with the associated road widening, the junction capacity of Wong Chuk Hang Road and Nam Long Shan Road will have a reserve capacity of 21% in 2011.

7.To accommodate the proposed flyover and the widened road, we have to demolish 1 an existing footbridge at the junction. Upon the commissioning of the flyover, we will reconstruct the affected section of Wong Chuk Hang Road and provide a permanent at-grade pedestrian crossing at the junction to replace the demolished footbridge.

8. We have investigated the possibility of using Heung Yip Road and Ocean Park Road as alternative routes to relieve the anticipated traffic congestion at the signalised junction as an alternative to building the proposed flyover. Such an option is considered unacceptable from a traffic engineering point of view due to the lack of adequate weaving length at critical road junctions. Furthermore, the additional diverted traffic from Nam Long Shan Road to Heung Yip Road and Ocean Park Road will create both capacity problems and safety concerns. A more detailed description of the traffic assessment is at Enclosure 1.

FINANCIAL IMPLICATIONS

9. We estimate the capital cost of the project to be $305.8 million in MOD prices (see paragraph 10 below), made up as follows -

$ million

(a) Flyover

150.0


(b) Road and drainage works

33.1


(c) Demolition of existing footbridge

1.2


(d) Traffic aids and landscape works

1.3


(e) Consultants' fee

29.0


(i) Construction stage

1.0



(ii) Resident site staff costs

28.0



(f) Contingencies

21.4


Sub-total

236.0

(at
December
1996
prices)

(g) Inflation allowance

69.8


Total

305.8

(in MOD
prices)

A breakdown by man months of the consultants' fees and resident site staff costs is at Enclosure 2.

10. Subject to approval, we will phase the expenditure as follows -

Year

$ million
(Dec 1996)

Price
adjustment
factor

$ million
(MOD)

1998 - 99

43.0

1.16358

50.0

1999 - 2000

115.0

1.26830

145.9

2000 - 2001

65.0

1.38244

89.9

2001 - 2002

10.0

1.50686

15.1

2002 - 2003

3.0

1.64248

4.9

_____


_____

236.0


305.8

_____


_____

11. We have derived the MOD estimates on the basis of the Government's forecast of trend labour and construction prices for the period 1998 to 2003. We will tender the proposed works under a re-measurement contract in view of the high proportion of foundation work for the flyover. The contract will provide for adjustments due to inflation as the contract period will exceed 21 months.

12. We estimate the annually recurrent expenditure to be $771,000.

PUBLIC CONSULTATION

13. We consulted the Traffic and Transport Committee (TTC) of the Southern District Board (SDB) on 20 January 1997. None of the DB Members present at the Committee Meeting objected to the project and the Committee conferred its support to the project. The Committee unanimously supported the project and requested its early implementation of the project to relieve traffic congestion in the Wong Chuk Hang area (particularly during peak hours) and to cater for future increases in traffic flow arising from the completion of various housing projects in the District. The Committee will set up a workingmonitoring group to reflect to the Administration any of any concerns which maymight arise duringin the construction stage of the project. to the Administration for formulation of suitable measures as necessar

14. We gazetted the proposed works under the Roads (Works, Use and Compensation) Ordinance on 4 April 1997 and 11 April 1997 respectively and received three objections 2.

15. The objectors were concerned about the inconvenience caused to the owners and tenants of adjacent buildings during the construction and commissioning of the flyover project. They were also worried about the environmental impacts brought about by the flyover project. We explained to the objectors the need for the proposed flyover and the resulting traffic benefits to the community. We also informed them that we had made an assessment of the possible environmental impacts on the area and that we would provide appropriate measures to ameliorate the impacts in accordance with established policies and standards. Consequently, all the three objectors withdrew their objections.

ENVIRONMENTAL IMPLICATIONS

16. We completed an Environmental Impact Assessment (EIA) study for the project in April 1997. The EIA concluded that the project would not cause any long term air or noise problems but recommended some environmental improvement measures including the planting of additional trees along the widened road as well as aesthetic treatment for the flyover.

17. The Advisory Council on the Environment was consulted on the project and advised that given its limited scale and complexity, there was no need for the EIA to be presented to them.

18. For short term impacts during construction, we will control noise, dust and site run-off through the implementation of mitigation measures in the works contract.

LAND ACQUISITION

19. The proposed works do not require any land acquisition. We shall remove 3 the projections from the industrial buildings facing Wong Chuk Hang Road along the stretch of the proposed flyover in order to maintain adequate clearance for the passage of vehicles, including emergency vehicles, on the widened carriageway.

BACKGROUND INFORMATION

20. We upgraded this project to Category B on 5 July 1995.

21. We engaged consultants in June 1996 to undertake the detailed design and investigation for the proposed works and charged the cost of $7.5 million to Subhead B100HX "Minor housing development related works, studies and investigations for items in Category D of the Public Works Programme". The consultants have substantially completed the detailed design, working drawings and tender documents. We plan to start the works in June 1998 for completion in November 2001.

22. To minimise disruption to traffic during construction, we will carry out the proposed work in stages and implement temporary traffic diversion schemes in consultation with the Police and the Transport Department to ensure that the principal traffic flows will be maintained during all stages of construction.

23. We submitted a paper to the Public Works Subcommittee (PWSC) on 10 December 1997 proposing the upgrading of 578TH to Category A (paper PWSC (97-98) 93). We withdrew the submission in view of Members' queries on possible alternative solutions which may be less environmentally intrusive. We agreed to include additional information to address this issue, as well as details of the discussions of the TTC of SDB on the proposed flyover, on the re-submission of the proposal to the PWSC for funding consideration. The required information has been provided in this paper.


Housing Bureau
January 1998

(HH614) 1.We shall demolish the existing footbridge after the commissioning of the flyover and the provision of the permanent at-grade pedestrian crossing. As the proposed flyover will carry the main through traffic, the signalised junction will have sufficient capacity to accommodate both the local vehicular and pedestrian traffics at grade. There is no need to reprovide a footbridge at the junction.

2. The three objectors are Rheingold (Hong Kong) Limited, owner of 39 and 41-43 Wong Chuk Hang Road, the Incorporated Owners of Po Chai Industrial Building and Ms. CHAN Oi-ling, owner of 1/F., Po Chai Industrial Building, 28 Wong Chuk Hang Road.

3. The Director of Buildings will clear the concerned projections from the industrial buildings from February 1998 to May 1998 at an estimated cost of $28 million. This will be charged to Head 701 - Land Acquisition Subhead 1100CA "Compensation and ex-gratia allowances in respect of projects in the Public Works Programme".

Enclosure 1 to PWSC (97-98)

578TH - Wong Chuk Hang Road flyover and associated road widening

Traffic assessment of the option of using Heung Yip Road and Ocean Park Road as alternative routes

We have investigated the use of Heung Yip Road and Ocean Park Road as alternative routes to relieve the traffic congestion at the signalised junction of Wong Chuk Hang Road and Nam Long Shan Road in lieu of the proposed flyover. Under such an arrangement, we would have to prohibit the right turning of traffic from Nam Long Shan Road to Wong Chuk Hang Road and to divert such traffic via Heung Yip Road and Ocean Park Road to Wong Chuk Hang Road for the signalised junction to operate within capacity. Sketch 1 illustrates the alternative route in question.

2. We consider that this proposal is unacceptable from a traffic engineering point of view because of inadequate weaving lengths at critical road junctions and capacity problems as detailed below :-

  1. There will be traffic congestion at the Heung Yip Road/Ocean Park Road roundabout and the flyover at Ocean Park Road. The existing weaving length from Heung Yip Road/Ocean Park Road roundabout to the ramp of the flyover at Ocean Park Road is only 50 metres. In addition, the capacity of the flyover is inadequate to cope with the anticipated increase in traffic flow which we estimate to be 800 passenger car units per hour by 2002. We have considered decking a portion of the adjacent nullah to increase the number of traffic lanes along Heung Yip Road and switching the said roundabout into a signalised junction to alleviate the weaving problem. Even if we did this, however, traffic congestion will still persist at the junction with a queue length of some 300 metres along Heung Yip Road because of the insufficient volume to capacity ratio of the flyover of Ocean Park Road. This problem could not be resolved without widening the flyover, a course of action which would require additional land and would be costly to implement.

    Sketch 2 illustrates the existing traffic movements at the concerned junctions.

  2. There will also be difficulties related to the Aberdeen Tunnel bound traffic from Ocean Park Road. The existing weaving length from the downramp of the flyover at Ocean Park Road to Wong Chuk Hang Road eastbound towards Aberdeen Tunnel is 90 metres. With the anticipated increase in traffic flow of 800 passenger car units per hour by 2002, the weaving length will have to be increased to 260 metres. This cannot be achieved due to site constraints. The lack of adequate weaving length will aggravate the traffic condition with queue length extending from the downramp of the flyover at Ocean Park Road to beyond the junction with Heung Yip Road, slowing down commuting movements in the local road network. Apart from the disruption to the traffic flow, insufficient weaving length would also be a potential safety hazard to motorists.

    We have considered widening the downramp of the flyover to 2 lanes to accommodate the additional traffic flow. Even if we did so, the problem of inadequate weaving length remains and sightline problems would exist for traffic moving towards the Aberdeen Tunnel. These problems could not be resolved without substantial modifications to the downramp and the adjoining structures, which again will require substantial land acquisition at significant cost.

    Sketch 3 illustrates the existing traffic movements at the concerned junction.

(HH614)

Enclosure 2 to PWSC(97-98)

578TH - Wong Chuk Hang Road flyover and associated road widening

Breakdown of estimates for consultants' fees

Consultants' staff costs


Estimated
man
months

Average
MPS*
salary
point

Multiplier
factor

Estimated
fee
($million)

(a) Administration of contract for construction stage

Professional

Technical

5.0

2.7

40

16

3.0

3.0

0.8

0.2

(b) Site supervision by resident site staff employed by the consultants

Professional

Technical

40.0

598.0

40

16

2.1

2.1

4.7

23.3





_____


Total consultants' staff costs

29.0



_____

*MPS = Master pay scale

Notes

1. A multiplier factor of 3 is applied to the average MPS point to arrive at the full staff costs including the consultants' overheads and profit, as the staff will be employed in the consultants' offices (At 1.4.96, MPS pt. 40 = $55,390 p.m., and MPS pt. 16 = $18,595 p.m.). A multiplier factor of 2.1 is applied in the case of site staff supplied by the consultant.

2. The consultants' fee for work in the construction stage is a provisional part of the lump sum price quoted by the selected consultants under Agreement No. CE 37/95 'Wong Chuk Hang Road flyover and associated road widening - design and construction' which is available for acceptance by Government subject to approval for upgrading 578TH to Category A.

(HH614)