PRINCES HIGHWAY - A history of the section from Adelaide to Tailem Bend

The Princes Highway is the major artery between Adelaide, Murray Bridge and beyond, connecting with the Dukes Highway and Mallee Highway at Tailem Bend. This section of the Princes Highway is almost entirely freeway, with only the single carriageway Swanport Bridge breaking the dual carriageway conditions. However, it wasn't always like that and this is the story of its journey from bush track to grade-separated highway.



In 1841 a road from Adelaide to Mount Barker was surveyed and constructed, allowing settlement in the Adelaide Hills. A toll house was establised at Glen Osmond to toll the road, thus paying for its upkeep and maintenance. However, the state of the road was poor and a sustained public backlash caused the removal of the tolls in 1847 after the Government refused to upgrade it any further.

In 1854 the first major realignment of the road was undertaken, improving the grades but creating the original Devil's Elbow corner. Later, between September 1867 and February 1868, a major deviation was constructed, with the new route bypassing the original Devil's Elbow via Overway Bridge. Thus, the Devil's Elbow name was transferred to a sharp corner near Mountain Hut, where it remains today.

The Overway Bridge deviation was to be the last major work on the road for a long time as the importance of railways grew. In 1877 construction of the railway line through the Adelaide Hills began, reaching Aldgate in 1883 and Murray Bridge in 1886.

The first bridge spanning the Murray River was completed in March 1879 at the town of Murray Bridge, carrying road and rail traffic from May 1886 until November 1925 when the rail-only bridge was opened. Until the rail-only bridge opened, traffic was being delayed for several hours at a time at the river crossing in order to allow trains to cross safely.


Early 20th Century

One of the first jobs of the Highway Department, formed in 1926 by the passing of the Highways Act, was to improve safety on the Mount Barker Road, particularly between Glen Osmond and Crafers. Thus, the road was sealed and linemarked in the late 1920s, a move which decreased incidents over the next few years. By 1936 the sealed road surface reached Murray Bridge.

Despite the safety improvements, the road was clearly inadequate for the amount of traffic it carried and thus investigations began into ways of improving the Mount Barker Road (named Princes Highway in 1938).


Plans for a Divided Highway between Glen Osmond and Crafers

Following World War 2, urban planning kicked into swing in South Australia and thus attention was again focused on the Princes Highway. "In anticipation of increased traffic flow over the South Eastern Road [Princes Highway] and in recognition of its deficiencies, plans were made for its realignment. Known as the Burnside-Crafers Highway, the proposed realignment left Greenhills Road and proceeded up Linden Ave then ascended the side of Waterfall Gully to join the South Eastern Road above Eagle On The Hill. Work started during 1949/50 and was undertaken by Burnside Council over three years. This project was eventually abandoned in favour of reconstructing the existing South Eastern Road."1

Thus, construction commenced in the 1950s on duplicating the existing highway. Jack McInnes, the engineer who helped design the upgrade said of the project: "We were obliged to undertake total reconstruction and widening - from Crafers to Glen Osmond - at high cost and significant engineering difficulty - of several forms. The alignment was so poor that no standards existed...constrained within a creek bed for much of the lower section, we enclosed the creek - contrary to good practice. Blasting of rock faces, 'holding' the down side by construction of 'benches' were difficult and dangerous. And all the while we were required to maintain two lanes of traffic flow. It was, in my view, the most difficult and dangerous enginnering task the [Highways] Department attempted in my time there - made even more difficult by increasing and heavier traffic volumes and, every year, several months of rain and fog."2

Work began in October 1952. The first section at Eagle On The Hill was completed in December 1953, and the next year work continued up the hill to provide a 12m wide pavement. During 1955/56 a new deviation to form the westbound carriageway was built between Measdays Hill and Crafers (old highway alignment now part of Hillcrest Ave). This deviation became known as the "Mad Mile" due to its steep falling gradient and straight alignment about a mile in length.

Once the idea for a Burnside-Crafers Highway was abandoned, reconstruction and widening of the most difficult section between Eagle On The Hill and Glen Osmond was commenced. Since it was impractical to construct temporary bypasses, the work was carried out alongside traffic. The first section reconstructed was from Mountain Hut (Devil's Elbow) to Young's Corner (300m south of Overway Bridge).

Further down the gorge, between 1958 and 1960 the Glen Osmond Creek was regraded and diverted into concrete pipes between Glen Osmond Rd and Mt Osmond Rd. This section was also widened. As part of the works, the intersection with Cross Road and Portrush Road was signalised. The level of Cross Road was raised to 9m above Glen Osmond Creek to provide easy gradients for vehicles at the intersection, and the road widened to four lanes. The 1.2km section between Mt Osmond Rd and the Mountain Hut was constructed during 1959/60. The last section to be tackled was the one had always proved to be the most difficult in the Highway's history: the last climb up to Eagle On The Hill. Work started on this section between Young's Corner and Eagle On The Hill in April 1960 and was completed in June 1961.


Rail proposal for the Adelaide Hills

In February 1962, Leader of the State Opposition, Frank Walsh, proposed a 39-mile rail tunnel through the Mt Lofty Ranges to link Adelaide and Murray Bridge. Mr Walsh claimed that a senior engineer in the Engineering and Water Supply Department had advised him there would be no engineering problems and a senior geologist with the Mines Department had endorsed this advice. The existing rail route was 60 miles and a trip took 2.5 hours, while the proposed electrified railway through the tunnel would be 39 miles in length and take 45mins. Mr Walsh sought Commonwealth Grants for the project, pointing to similar schemes funded by the Commonwealth interstate (e.g. Snowy Mountains). Unfortunately nothing evenutated from this proposal, squashed by the freeway-centric planning of the time.


South Eastern Freeway

Following the duplication from Glen Osmond to Crafers, a solution was needed for the remainder of the Princes Highway from Crafers to Murray Bridge. The Highways Department proposed a new high standard, grade separated highway to replace the narrow, widning and tortuous route between Crafers and Mount Barker. Not long after, it was decided the freeway would extend to Callington.

In October 1960 Minister for Roads, Norman Jude, introduced a bill to parliament anabling the Government to build freeways and operate them as controlled access roads. This paved the way fro the construction of the South Eastern Freeway.

In February 1962 an American consultant was commissioned to advise the Highways Department on a proposed first section of the South Eastern Freeway. The Department had never constructed a freeway before and the concept had only recently been introduced to Australia so the American consultant brought some very valuable experience to the state. The preliminary designs were completed in May 1962 and released to the public. Some controversy erupted over the proposed first stage - from Crafers to Verdun - because the proposed route passed through Arbury Park. Opposition was found at a political level too from MP Alexander Downer - the freeway was proposed to pass by the front of his house. Downer offered to land behind his house to the Department for free but the adoption of a more northerly alignment behind Downer's house would have resulted in much higher construction costs and a greater scar on the landscape. Premier Thomas Playford listened to the opposition before meeting with the Commissioner for Highways who showed him that it was the only viable route. Downer eventually gave up the fight when he accepted a job in Port Augusta and relocated. Construction commenced in December 1965 however, due to ongoing negotiations regarding the route near Arbury Park, the first stage was limited to a 2km section from Measdays Hill to Stirling. This section consisted primarily of duplicating the existing Princes Highway, with a small deviation and grade-separated interchange constructed at Summit Road, Crafers. In February 1967 the northern (eastbound) carriageway was opened to traffic, although the section of freeway was not officially opened by the Minister for Roads and Transport until February 1969. The section was fully completed in May 1969 when the Crafers Interchange became fully operational.

In February 1972 Commissioner for Highways, Keith Johinke, announced that the South Eastern Freeway would extend from Callington to bypass Murray Bridge, caliming that this would be cheaper than upgrading the existing road to a similar standard. However, the real reason for this extension was uncovered in November when Premier Don Dunstan announced a site near Murray bridge had been chosen for the new city of Murray, later renamed Monarto.

The next stage, extending the freeway eastward behind Arbury Park and through Bridgewater to Verdun was completed in May 1972. This section was agruably the most important of them all as it bypassed the shopping strips of Stirling and Bridgewater as well as some narrow, winding and tortuous lengths of highway.

Two years later, in December 1974, the freeway was extended from Verdun to Mount Barker, bypassing the small village of Hahndorf. The freeway reached Callington in December 1977, with National Highway 1 using a section of the Callington-Strathalbyn Rd to connect the freeway with Princes Highway (one sign remains).

Because the South Eastern Freeway was proclaimed a National Highway in November 1974, future sections of the freeway were eleigible for federal funding. This enabled the freeway to be completed much sooner than if the State had been required to fund it. In May 1979, the South Eastern Freeway was completed, being extended east from Callington across the Murray River on the Swanport Bridge to join the Princes Highway east of Murray Bridge. The Swanport Bridge is the official terminus of the South Eastern Freeway (as it is single carriageway) and the remainder of the Murray Bridge bypass was known as the Swanport Deviation until the Princes Highway name was apllied to the entire route in 2000. Also, as part of the construction of the Swanport Deviation, the dual carriageway conditions were extended 22km east along the Princes Highway to Tailem Bend, including the bypass of the town centre.


Adelaide-Crafers Highway

Following the completion of the South Eastern Freeway in 1979 attention was again turned to the Glen Osmond-Crafers section of Princes Highway. Having been proclaimed a National Highway in November 1974 the Princes Highway was eleigible for 100% federal funding and thus the Highways Department began considering various suggested solutions for improved connections between the South Eastern Freeway and metropolitan Adelaide. These included upgrading the Upper Sturt Road and the construction of new roads along Sheoak Rd and between Burnside and Crafers.

"By 1983 three alternative proposals had been the subject of preliminary investigations: construction of twin 500m tunnels through Wylies Hill at Union Quarry; an alignment that allowed Fullarton Rd to connect to Eagle On The Hill past Brown Hill; and alignment adjustments and installation of a narrow median on the existing Princes Highway. Despite an estimated cost of $15 million (1983), this latter proposal would not meet National Highway standards."3

Commissioner for Highways, Michael Knight, approved a planning study to examine new options for upgrading Princes Highway and, in April 1986, Maunsell and Partners were appointed to undertake a study of alternatives for upgrading the existing highway from Adelaide to Crafers.

Craig McLean, Project Manager (Maunsell & Partners): "More than 30 possible alignments were generated and broadly tested for adequacy in engineering, environmental and cost terms. They included options that abandoned the Toll Gate entry to the city, such as connections to Fullarton or Greenhills Roads. The Greenhills Road options interefered with Waterfall Gully and Cleland Conservation Park and were technically unnattractive.
"Eight promising routes were selected for more detailed study. Consideration of social, visual, ecological, heritage and traffic issues allowed the delineation of a minimum impact area, elimination of less favourable options and adaptations of the remaining options to the constraints that had been defined. Our assessment also clearly demonstarted that Fullarton Road would not be acceptable as a connection. Such a connection offered the only opportunities for a route without tunnels, but the massive acquisitions that would be needed along Fullarton Rd to distribute traffic into Adelaide eliminated this advantage."4

The eight shortlisted options were presented for public comment in October 1986 and in December 1986 suveying of the selected route was undertaken. In March 1987 Deputy Commissioner for Highways, Jack McInnes, announced that option C1 had been selected, incorporating the existing highway from Glen Osmond to Devil's Elbow and a new alignment from Devil's Elbow to Crafers. He estimated that the cost would be in the vicinity of $100 million (1987).

In July 1987 a supplement to the Draft Environmental Impact Statement was released, detailing the final proposal, C3 - a modified version of option C1 that did not encroach into Cleland Conservation Park. The Federal Government approved the route in February 1989 however, the project stalled when the Federal Labour Government changed its funding priorities to enable the completion of major construction projects in the eastern states.

As an interim measure, the Highways Department spent $7 million on upgrading the existing highway, including: special non-skid ashphalt; median adjustments; and signage, drainage and lighting upgrades; and was completed in 1989. The public were concerned that these interim measures would distract the Government from pushing hard for federal funding for the new highway. State Highways Minister Gavin Keneally gave assurance in June 1989 that: "We have every interntion to continue pressing for a new and better road. There is absolutely no indication that the Federal Government has changed its attitude. It is obvious that the new alignment (whatever is finally decided) cannot be provided for some years and in the interim something has to be done to the existing road."5

The project remained in limbo for a number of years until finally, on 16 May 1995, Prime Minister Paul Keating made this public announcment: "I am pleased to announce today that the Commonwealth Government will undertake in South Australia two major infrastructure projects: the Mount Barker Road and the extension of Adelaide Airport. The Mount Barker Road project, the estimated cost of which is $130 million, will be funded from the Commonwealth's National Highways program."6

Pre-construction work commenced almost immediately after that announcement was made and, in February 1996, an official ceremony was held to mark the turning of the first sod.

The first item of work was constructing a new section of road between Mirra Monte Estate and Mt Osmond Road so that traffic could be switched to this section and enable work to begin on filling the valley and raising the road height by 12m. The major cuttings were constructed after tempoary diversion roads were completed to carry the highway traffic.

"Minimising the environmental impact on the Adelaide Hills was a priority when Maunsell and Partners were given the task of designing the highway. One way this was done was by using steep cuts into the hills. Gentler cuts, or cuts over a wider distance, would have disturbed more vegetation and widlife."7

Major milestones were reached towards the end of 1998 with both tunnels being cut through to daylight more than three weeks early. In November 1999 the Mount Osmond Road interchange was opened to traffic, paving the way for the opening of the Adelaide-Crafers Highway (including the two Heysen Tunnels) on 5 March 2000. At opening the Princes Highway name was bestowed on the entire freeway route from Glen Osmond to east of Murray Bridge.

The 30 upgrade options studied.
Source: Cockburn et. al; 2000
(Click to Enlarge)

The 8 upgrade options selected for more detailed study.
Source: Cockburn et. al; 2000
(Click to Enlarge)

Map showing the interim upgrade measures installed by the Highways Department in 1987.
Source: Cockburn et. al; 2000
(Click to Enlarge)

1. Cockburn, S., Ruff-Hewitt, M., Linn, R. & Stacey, B., Highway through the Hills: The Story of Mount Barker Road; 2000; p. 38-39
2. Donovan, P.; Highways: A History of the South Australian Highways Department; 1991; p. 143-144
3. Cockburn, S., Ruff-Hewitt, M., Linn, R. & Stacey, B., Highway through the Hills: The Story of Mount Barker Road; 2000; p. 52
4. Cockburn, S., Ruff-Hewitt, M., Linn, R. & Stacey, B., Highway through the Hills: The Story of Mount Barker Road; 2000; p. 53
5. Cockburn, S., Ruff-Hewitt, M., Linn, R. & Stacey, B., Highway through the Hills: The Story of Mount Barker Road; 2000; p. 60
6. Cockburn, S., Ruff-Hewitt, M., Linn, R. & Stacey, B., Highway through the Hills: The Story of Mount Barker Road; 2000; p. 64
7. Cockburn, S., Ruff-Hewitt, M., Linn, R. & Stacey, B., Highway through the Hills: The Story of Mount Barker Road; 2000; p. 66

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