Timeline of duplication

• 1964/65 – Ballarat East. 2.4 miles (3.9 km) of duplicate carriageway completed east of Ballarat. No exact date given.^[7] Now part of Route C805 leading from the Western Freeway into Ballarat from the east.
• 1966/67 – Deer Park to Rockbank. 7.12 miles (11.46 km) of dual carriageways completed during financial year 1966/67.^[8] Part of this is now Ballarat Road, Metro Route 8 through Deer Park and Caroline Springs.
• 1966/67 – Dual carriageways from Djerriwarrh Creek to Coimadai Creek completed during financial year 1966/67.^[8] Now part of Bacchus Marsh Road between Melton and Bacchus Marsh.
• 1966/67 – Dual carriageways 1.83 miles (2.95 km) east of Pykes Creek Reservoir completed during financial year 1966/67.^[8]
• 1967/68 – Rockbank to Melton East. Construction completed of over 3 miles (4.8 km) of dual carriageways during financial year 1967/68.^[9]
• 1969 – Pykes Creek Reservoir. The ‘Western By-pass Road’ is completed, running four miles east and west of Pykes Creek Reservoir.^[10]
• 1972 – Bacchus Marsh bypass. 5.88 miles (9.46 km) opened 30 June 1972, by the Hon. Sir Henry Bolte, GCMG, MP, at a cost of A$4.3m.^[11]
• 1972 – Gordon section. 5.74 miles (9.24 km) opened 5 May 1972, by the Board's chairman, Mr R E V Donaldson, at a cost of A$2.2m.^[11]
• 1973 – Pentland Hills to Myrniong section. 1 mile (1.6 km) completed from Korkuperrimul Creek to the Lion Park interchange, early 1973.^[12]
• 1974 – Pentland Hills section. 4.8 kilometres (3.0 mi) ‘west of Bacchus Marsh’ opened 1974.^[13]
• 1975 – Myrniong bypass opened 3 October 1975, by the Minister for Transport, the Hon. E. R. Meagher, CBE, ED, at a cost of A$3.28m. The 5.9 kilometres (3.7 mi) bypass of Myrniong completed '80 km of dual carriageways between Melbourne and Ballarat'.^[14]
• 1978 – Ballan bypass. 8.4 kilometres (5.2 mi) opened 15 June 1978, by the Hon. J. A. Rafferty, Minister for Transport, at a cost of A$9.8m.^[15]
• 1983 – Wallace and Bungaree bypass opened 9 March 1983, by the Premier of Victoria, the Hon. John Cain MP. The 11.9 kilometres (7.4 mi) bypass cost A$23.6m.^[16]
• 1987 – Melton bypass. The 'freeway work' was opened to traffic on 7 July 1987, with the remainder of works expected to be completed by April 1988. The 8.8 kilometres (5.5 mi) bypass cost A$44.2m.^[17][18]
• 1989 – 5.6 km bypass of Dimboola opened in May.^[19]
• 1993 – Ballarat bypass. The first stage, a single carriageway section from Woodmans Hill to the Midland Highway, is opened in December 1993, at a cost of A$62m.^[20]
• 1994 – Ballarat bypass. The second stage of the initial 26 kilometres (16 mi) single carriageway by-pass is opened to traffic in December 1994.^[21]
• 1995 – Ballarat bypass. Second carriageway opened to traffic between Woodmans Hill and Gillies Street in December 1995, at a cost of A$25m.^[22]
• 1998 – Ballarat bypass. The final section opened in February 1998, The final stage featured the duplication of the original single carriageway bypass from Gillies Street to the Sunraysia Highway.^[23]
• 2001 – The new elevated Hopkins Road Interchange was opened to traffic on 12 July 2001, at a cost of $13.1 million.^[24] Before the construction of the new interchange, the intersection of Hopkins Road (Melton-Werribee Road) with the Western Freeway at Rockbank was improved using Black Spot Program funds in 1989 and 1991, but a long-term solution to the congestion and crashes at this location was the construction of an elevated interchange.^[25]
• 2009 – Deer Park bypass opened to traffic on 5 April 2009, at a cost of A$331m, jointly funded by the state and federal governments. In conjunction with these works, the new Leakes Road interchange at Rockbank was opened in August 2008.^[26] This provided a freeway interchange onto the Western Ring Road.
• 2011 – Anthony's Cutting realignment. A new 5-kilometre (3.1 mi) realignment constructed to the south of the previous section of highway, bypassing the steep grades and tight curves of the old alignment between Melton and Bacchus Marsh. The A$200m project was ‘mostly’ open to traffic in June 2011.^[27]
• 2013 – Ballarat to Burrumbeet. 8 kilometres (5.0 mi) duplication opened to traffic 31 January 2013.^[28]
• 2015 – Burrumbeet to Beaufort opened to traffic on 18 February 2015 adding a further 26 kilometres (16 mi) of dual carriageway and includes a bypass of Trawalla however the highway still passes through both Burrumbeet (as dual carriageway) and Beaufort (as single carriageway).^[29]
• 2016 – Beaufort to Buangor opened to traffic in April 2016 adding a further 21 kilometres (13 mi) of dual carriageway to the existing freeway, which includes the Buangor bypass.

Deer Park Bypass

Eastbound on the Deer Park Bypass approaching the Western Ring Road interchange

The Deer Park Bypass opened on 5 April 2009 in the western suburbs of Melbourne. The freeway links the Western Freeway at Ravenhall, and the Western Ring Road in Derrimut. This 9.3 kilometre freeway was estimated to cost A$333 million which also includes a grade separated interchange or a "full diamond" at Leakes Road in Rockbank.

The purpose of the freeway bypass is to move traffic off Ballarat Road, which leads to the Western Ring Road. Due to the strong population growth of about 8.7 per cent and subdivision in Deer Park and Sunshine, the surrounding suburbs and the seven traffic signals between the Western Ring Road and the start of the Western Freeway, substantial long and very frustrating delays were created for the 70,000 vehicles per day with 10 per cent of this consisting of heavy vehicles.

The bypass had been proposed since the completion of the Western Ring Road, the project stalled due to funding quarrels between the Federal and State Governments. In 2004, the Federal government announced that the Deer Park Bypass would be built as part of a $1.4 billion project "package grant" to Victoria. It was anticipated that more than 15 min of travel time would be saved when travelling through Deer Park, via Ballarat Road.

Construction started on the Deer Park bypass in August 2006,^[30] work being carried out as a joint venture by Leighton Contractors and VicRoads, in construction with two contracts. The first stage, allowing westbound traffic over the new bridge at the Ravenhall end of the new freeway, opened in December 2007.^[31]

It was announced on 4 March 2009 that the Deer Park Bypass would open in early April 2009, with the new freeway link on track to open more than eight months ahead of schedule.

On that day, Roads and Ports Minister Tim Pallas and Federal Member for Gorton Brendan O'Connor MP inspected works from the new bridge over the Ring Road at Sunshine West and Tim Pallas announced that the $331 million Deer Park Bypass would open to the public on Sunday 5 April 2009.^[32]

Anthony's Cutting realignment

Alignment of the road over Djerriwarrh Creek, before the opening of the Anthony's Cutting realignment

The section of road through Anthony's Cutting between Bacchus Marsh and Melton was one of the most dangerous sections of the route, and was not of modern freeway standard. The steep hills and tight curves along the 5 kilometre long stretch of road resulted in 21 serious crashes in the five years to 2010.^[33] More than 29,000 vehicles, including more than 4000 freight vehicles, travel the highway section daily.^[34] The new route opened to traffic on 27 June 2011, nine months ahead of schedule.^[35]

The project included:^[36]

• Extension of Woolpack Road north from Bacchus Marsh Road to a new interchange on the Western Freeway, including a bridge over the Lerderderg River.
• An overpass carrying Bulmans Road over the existing Western Freeway.
• An overpass taking Hopetoun Park Road across the new freeway, with Melbourne-bound on and off ramps.
• Freeway bridges spanning Djerriwarrh Creek, and Cowans Road / Pyrites Creek.

The original project scope included a diamond interchange at Bulmans Road that has not been built, while the ramps at Hopetoun Park Road were not included but was later added.^[37] The extension of Woolpack Road has been delayed due to controversy over need to clear trees in the heritage listed Avenue of Honour at Bacchus Marsh.^[38]

Realignment of the road through this section had been proposed far back as 2001, when a group of 10 local councils said the realignment could cost just $65 million to build.^[39] By 2006 the cost was estimated to be $85 million, with federal Roads Minister Jim Lloyd stating that the project would receive serious consideration for funding in the 2009 AusLink document, subject to support from the State Government.^[40] Construction commenced in February 2010, funded by $160 million from the Australian Government and $40 million from the Victorian Government.^[41]

Armstrong deviation

In 2001 work started on a 4.2 kilometre long deviation at Armstrong (on the Adelaide side of Ararat), involving 200,000 cubic metres of earthworks and a new bridge over the main Melbourne–Adelaide railway. Previously high vehicles could not travel under the rail overpass and were forced to detour around it, in addition the poor road conditions led to a number of accidents and fatalities.^[42] Costing $6.1 million the work was completed by 2003.^[43]