The Eastern Distributor is a motorway in Sydney, New South Wales, Australia. Part of the M1, 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 75.1% owned by Transurban.
The motorway opened to traffic in December 1999 with the project completed in July 2000. It is only tolled in the northbound direction.
Transurban considers the southern end of the Cahill Expressway (including the Domain Tunnel) 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 (Cowper Wharf Road) and the northern end of Southern Cross Drive (Link Road).
Design
This motorway is part of the Sydney Orbital Network. For about half its length, it is in a trench inside South Dowling Street. The motorway provides a southbound exit for Lachlan Street/Dacey Avenue, a northbound exit to South Dowling Street (south of Cleveland Street), a northbound entrance ramp from South Dowling Street (north of Cleveland Street), connections from William Street (heading south), and to William Street (heading north). There are also connection to the Cross City Tunnel, giving motorists direct connections under the city to the Western Distributor. There are also northbound/southbound entry/exits to Moore Park Road and Anzac Parade. Southbound motorists were later found to be entering the Eastern Distributor from the Cross City Tunnel access point and immediately attempting to cross three lanes for the Anzac Parade off-ramp. Permanent traffic obstacles have subsequently been installed and users are now referred to the Lachlan Street/Dacey Avenue exit, or as through traffic towards Sydney Airport.
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 (rail or road) 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.
TAt 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 (from the ceiling to the floor).
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.