Eastern Distributor


The Eastern Distributor is a motorway in Sydney, New South Wales, Australia. Part of the M1 and the Sydney Orbital Network, the motorway links the Sydney central business district with the south-east and Sydney Airport. The Eastern Distributor separates Sydney's Eastern Suburbs from Sydney's Inner-Southern Suburbs. The centre-piece is a tunnel running from Woolloomooloo to Surry Hills. Built as a build-own-operate-transfer project, it is 75% owned by Transurban.
The motorway opened to traffic in December 1999, with the project fully completed in July 2000. It is only tolled in the northbound direction.
Transurban considers the southern end of Cahill Expressway to be part of the Eastern Distributor, and denotes the latter to have a total length of. The length of used in this article refers to the length of the motorway constructed in the 1990s between the southern end of Cahill Expressway and the northern end of Southern Cross Drive.

Route

The Eastern Distributor commences at the southern end of Cahill Expressway and the interchange with Cowper Wharf Road in Woolloomooloo and heads in a southerly direction as a dual-carriageway six-lane surface road, before entering piggyback tunnels shortly afterwards under the suburbs of Woolloomooloo and Darlinghurst, with a subterranean interchange with the Cross City Tunnel for direct connections to the Western Distributor. After returning to the surface in Moore Park, it continues south in a trench inside South Dowling Street, before ending at the interchange with Link Road and continuing south as Southern Cross Drive.

Design

The project's centrepiece is the piggyback tunnel under one of Australia's most densely populated urban areas, necessitated due to the requirement of three lanes in each direction within the existing roadway corridor. The unique double-deck, three lanes per direction design comprises a large, single tunnel excavation. At mid-height through the excavation, a precast concrete ledge forms the base of the northbound tunnel, with the southbound tunnel slotting below. As a result, only one tunnel roof was created with the lower southbound carriageway built in a slot. According to the Australasian Tunnelling Society, no records are available of any piggyback tunnel where the upper carriageway has been carried on prestressed concrete planks resting on sidewall ledges. In the main tunnel there is a central length of where the span is typically greater than, and of note, there is no record of any road tunnel with spans greater than this where permanent roof support comprises rockbolts and shotcrete only and with vertical unsupported sidewalls of rock.
At the time it was built, the tunnel's claim to fame was that at across at its widest point, it was the widest tunnel in the world. This point occurs where the William Street on ramp tunnel merges with the main tunnel. At, the tunnel is also notably tall.
The tunnels of the Eastern Distributor are fully equipped with lighting, ventilation, drainage, CCTV surveillance, fire fighting and emergency control systems.

History

County of Cumberland planning scheme

The need for an Eastern Distributor was first discussed in the early 1950s in the County of Cumberland planning scheme.
Underpasses of the Eastern Distributor beneath William Street and Taylor Street were proposed to commence construction in 1974. The construction never eventuated.

1984 scheme

In 1984, the Department of Main Roads proposed construction of the Eastern Distributor as a surface freeway with underpasses at William Street and Oxford Street. It was later redesigned into a tunnel from north of William Street to the intersections of South Dowling Street, Moore Park Road and Anzac Parade. An Environmental Impact Statement was prepared on 1985 to be built in three stages:
  • Stage 1: A southbound tunnel underpass under William Street and a roundabout at the Riley Street / Sir John Young Crescent intersection, scheduled for completion in 1988
  • Stage 2: Southbound tunnel for the full length and a reconfigured Cahill Expressway intersection with Sir John Young Crescent. Bourke Street and Palmer Street including the William Street underpass would also be reversed for northbound travel. Stage 2 was scheduled for completion in 1990
  • Stage 3: Northbound tunnel from Flinders Street connecting directly to the William Street underpass, scheduled for completion in 1992
The William Street underpass opened in November 1987 and connected Cahill Expressway and Palmer Street to Bourke Street. The underpass allowed southbound traffic from Cahill Expressway to avoid intersecting William Street. The rest of the 1984 scheme was abandoned and not constructed due to escalating costs. The William Street underpass would eventually be closed twelve years later after the main Eastern Distributor tunnels opened to traffic in December 1999, to be reconstructed to form part of the Bourke Street on-ramp which opened seven months later.

1994 scheme

The completion of the Sydney Harbour Tunnel in 1992 resulted in an increase in volumes on Cahill Expressway and therefore an increased need for an inner-city bypass south and south-east of the expressway. Roads & Traffic Authority undertook community consultation to gauge the level of community acceptance of construction of the Eastern Distributor as a toll road. With indications of a high level of community support, the Eastern Distributor project was revived by the New South Wales state government in 1994, based on the 1984 scheme. The Eastern Distributor would link the Sydney central business district with Sydney Airport via the already existing Southern Cross Drive, which would be widened. It was designed to ease congestion and to reduce the time to travel from the city to the airport by bypassing 19 traffic lights. A study commissioned by the State Chamber of Commerce in 1997 found that the "Eastern Distributor would prevent 330 accidents a year and cut fuel consumption by 1.2 million litres annually".

Tender process

In May 1994, the state government gave approval for RTA to invite the private sector to tender to construct and operate the tollway under a build-own-operate-transfer arrangement. In February and March 1995, three proponents were invited to develop detailed proposals. The RTA later requested the proponents to submit revised offers based on a concession term of 38 years, as "a term of 45 years would be unacceptable to the community" and the 38 year term had already been set as a precedent by the M2 Motorway.
The Labor state opposition promised that if elected, the Eastern Distributor would be toll-free. When Labor was elected as government in March 1995, the formal tender process had already commenced, and the new government had to proceed with constructing the Eastern Distributor as a tollway. In November 1995, the government agreed with RTA's recommendation to appoint Airport Motorway Limited as the successful proponent, with the government providing planning, support and management during construction. The other two unsuccessful proponents were Baulderstone Hornibrook and Transfield.
The Keating federal government announced on 15 December 1995 that it intended to withdraw taxation concessions on infrastructure bonds for urban road projects, "effective immediately". In a response letter written to the federal treasurer Ralph Willis in January 1996, the state treasurer Michael Egan highlighted that the policy would impact the M5 East and Eastern Distributor projects, and estimated that the policy would result in an "increase the cost of the Eastern Distributor project by between $70 million and $90 million". As a result, the announcement was "sufficient to halt the progress of the Eastern Distributor project" and the appointment of AML as the successful proponent was not formally endorsed. The policy was not enacted into legislation by the Keating government prior to the March 1996 federal election. The newly-elected Howard government reversed the policy in June 1996 and confirmed that the Eastern Distributor has been certified as "an urban road project which may utilise infrastructure bonds for financing purposes".
Following the reversal of the federal government policy, on 13 August 1996 the appointment of AML as the successful proponent and the decision to proceed with the project was formally announced. The agreement was signed in 1997, and under the concession agreement, AML would own and operate the tollway for 38 years after full opening.

Planning

In 1994, RTA decided to delay the EIS until after the selection of the preferred proponent, explaining that if an EIS was prepared then, then "it is unlikely to
contain the most innovative solutions to construction and environmental issues and could require a further EIS being required before work could commence". However, there would be a risk that substantial changes to the EIS would risk a new tender.
The EIS for the Eastern Distributor was eventually exhibited in November to December 1996. 2,762 submissions were received during the exhibition period. RTA proposed significant modifications in April 1997, which included:
  • a landscaped canopy over the northern end of the motorway near the Art Gallery
  • relocation of the northern tunnel portal north of Cathedral Street
  • lowering of the motorway in a trench between South Dowling Street
Due to the substantial modifications, RTA sought advice from the Independent Commission Against Corruption on whether a new tender was required; ICAC later advised that it was not required. The proposed modifications increased project costs by. As a result, the concession period was increased from 38 to 48 years, and the opening toll price was also increased from to.
The New South Wales Audit Office undertook a performance audit of the proposed tollway and tabled its report in Parliament on 28 May 1997, with the report finalised in July 1997. A planning assessment report by the Director-General of Department of Urban Affairs and Planning was published on 2 June 1997, and the project was approved by the Minister for Urban Affairs and Planning on 26 June 1997, subject to 151 conditions. Actual construction started soon after in August 1997.
The passing of the Roads Act of 1993 updated road classifications and the way they could be declared within New South Wales. Under this act, the Roads & Traffic Authority declared the Eastern Distributor as Tollway 6007, from its interchange with the Cahill Expressway and Cowper Wharf Road in Woolloomooloo to the interchange with Southern Cross Drive and Link Road in Kensington, on 4 July 1997, just before it started construction and 2.5 years before it had officially opened; the tollway today still retains this declaration.