Southern Expressway

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The Expressway near its northern terminus (looking north) showing the Seacombe Road bridge, at Marion.

The Southern Expressway is the world's longest reversible one way freeway. Originally proposed as 'Noarlunga Freeway', it was built as a corridor to relieve heavy traffic from the major arterial, Main South Road in Adelaide's south. The expressway was built in two stages—the first completed in late 1997 and the second was completed in 2001. The total cost of the arterial was A$76.5m, and it is 21 km in total length. There is a provision for the future duplication of the expressway when the time arises [1]. The Southern Expressway is signed as M2.

The Southern Expressway is open approximately 22.5 hours per day - a one-way freeway operating for over 11 hours in each direction. The northbound direction occurs on weekday mornings and weekend evenings, the southbound direction occurs on weekday evenings and weekend mornings. It is closed between approximately 12:40am - 1:10am and 12:30pm - 1:30pm except for Saturday and Monday mornings when the direction remains unchanged. The official closing times given by Transport SA are between 12:30am - 2:00am and 12:30pm - 2:00pm. During each closure all road signs, lights and boom gates switch, and the road is inspected by an RAA van for debris or car breakdowns.

Main South Road provides both the start and finish. There are exits at Marion Road, Panalatinga Road, Sherriffs Road and Beach Road.

Construction of the Expressway also included the Veloway for the exclusive use of cyclists that runs alongside the Southern Expressway for a distance of 7 km — from Marion/Main South Road to the Panalatinga Tunnel. South of the Panalatinga Tunnel, the bikeway becomes a shared track for the remaining 12 km of the Southern Expressway.

[edit] History

Main South Road at the northern end of the Expressway (looking south), closed to south-bound traffic.

The Southern Expressway is the southern part of a north-south freeway originally conceptualised under the Metropolitan Adelaide Transport Study (MATS), completed in 1965. The original proposal was for a freeway bypassing the city that ran from Dry Creek to Old Noarlunga [2]. The MATS plan proved unpopular, and in 1971 all further highway construction in Adelaide was postponed for a period of ten years. In 1983 plans for the freeway north of Darlington were abandoned, and the land that had been set aside was progressively sold off.

In 1984 the state government announced plans to develop a "third arterial road" for the south. In 1987 the project was split into two phases, the first the upgrading of Main South Road and Marion Road around the Darlington area, and the second a new road from Darlington to Reynella. Phase one was completed in 1994 with the widening of Main South Road to eight lanes between Ayliffes Road and Seacombe Road, and the widening of Marion Road to six lanes between Main South Road and Sturt Road.

Phase 2 became the "Southern Expressway", which was to be constructed in two stages: the first from Darlington to Reynella, and the second from Reynella to Old Noarlunga. It was developed as a one-way reversible road with future duplication provided for in the roadworks base, to be constructed when the need arose. It utilised the remaining "Noarlunga Freeway" reservation, except for the northernmost kilometre where a new route through O'Halloran Hill was chosen to provide high quality links with Marion and Main South Roads without interfering with existing infrastructure at Sturt.

Construction of the Southern Expressway commenced in July 1995 and the first stage was opened to traffic on 17 December 1997. Construction commenced on the second stage in February 1999 and was opened to traffic on 9 September 2001.

Although a boon to residents living a substantial distance south of the CBD, the expressway itself does not commence until some 15km south of the CBD. This fact, combined with its one-way operation, design compromises and the fact that it bypasses large sections of existing freeway-class road, have lead many to question its benefit.

[edit] Bridges

The 15 bridges over the Southern Expressway are named from north to south as follows:

The Southern Expressway has four underpasses:

[edit] Reference

• Adelaide's Freeways - A History from MATS to the Port River Expressway

[edit] External link

• Southern Expressway Traffic Management System Transport SA