Initially constructed between 1925 and 1930, this section of Pacific Highway was developed as part of the major project to provide a significantly improved road connection between Sydney and Newcastle. Constructed to the standards of the time through difficult terrain, the original highway comprised a narrow two-lane pavement on a sinuous alignment. Whilst the grades were reasonably easy, the highway curved continuously as it climbed out of the Mooney Mooney Creek valley, crossed the lower Somersby Plateau, descended to cross Piles Creek on a low-level bridge and once again ascended to the plateau at Kariong.

The Calga-Gosford-Ourimbah section of Pacific Highway was relieved of a significant proportion of its through traffic burden in 1964,^[1] with the opening of State Highway No. 26 (Peats Ridge Road), however it continued to carry heavy traffic to Gosford, Terrigal and the lower Central Coast. Significant improvements were not proposed for this section as the Department of Main Roads envisaged that the future construction of the F3 Sydney-Newcastle Freeway would relieve this section of through traffic.

From 1965 onwards, the preferred alignment for the F3 between Mt White and Ourimbah left the existing freeway at the heavy vehicle checking stations, proceeding eastward across Mooney Mooney Creek before ascending to the plateau along the eastern side of Piles Creek. This route would have resulted in an interchange being constructed roughly at the location of the present Central Coast Highway/Kangoo Road intersection. In 1978 a new route for the freeway was selected (the present alignment) crossing Mooney Mooney Creek upstream of the Pacific Highway bridge and cutting a swathe across the top of the ridge between Mooney Mooney and Piles Creek.^[2] To make room for the freeway alignment, a 3.5km section of Pacific Highway had to be relocated, as shown on the map above. A short section of Wisemans Ferry Road (Main Road No. 225) was also relocated to form part of the interchange approach roads.

Commenced in 1981, the deviation involved constructing 5.4km of new, mostly two-lane road, along with two four-lane sections now in use as part of the freeway interchange approaches. It was opened to traffic in October 1983 at a cost of $4 million.^[3]

The bypassed section of highway was generally abandoned, with a small section (marked E on the map) retained for access to Boral's Gosford Quarries. The remaining sections are in various states of overgrowth, however there are a few nice little bits if highway archaeology to find if you know where to look.

References:

[1] 'New Route for Traffic, Calga-Peat's Ridge-Ourimbah' in Main Roads, Vol. 29, No. 3, March 1964, p. 65
[2] Department of Main Roads, 1980, Sydney-Newcastle Freeway, Freeway F3, Section: Mount White to Ourimbah, National Highway Project No. 212A, Environmental Impact Statement. Sydney: DMR.
[3] 'The F3 Taking Shape: Sydney Newcastle Freeway' in Main Roads, Vol. 48, No. 4, December 1983, p. 102

• Section A
• Section B
• Section C
• Section E
• Section F
• Section G
• Section H

Section A

A short section of remnant pavement remains as the old alignment branches off to the north. Beyond about 20-30 metres the pavement has been ripped up and the alignment overgrown. There is a small portion of old pavement at the northern end of this section, surviving in the grass.

	The southern/western end of the deviation, showing the old alignment branching off to the right into the bushes. Source: Adam Sadler, January 2011.
	A closer view of the southern end of the old alignment, showing remnant centre line. Just beyond the gate, the pavement has been ripped up and the formation is now heavily overgrown. Source: Adam Sadler, January 2011.
	A small piece of the old pavement remains just before the old meets the new at the northern end of Section A. Source: Adam Sadler, September 2008.
	A view southwards from the current alignment at the northern end of Section A, showing the overgrown formation. Source: Adam Sadler, September 2008.

Section B

This section is heavily overgrown and almost impenetrable. No pavement remains.

	Looking north from the current alignment at the southern end of Section B. The formation is heavily overgrown but a small part of the old cutting is visible. Source: Adam Sadler, September 2008.
	After bush-bashing his way through the near impenetrable vegetation on Section B, Adam Sadler managed this shot looking north across the massive freeway cutting towards the southern end of Section C. The present overbridge across the freeway is located to the right of shot. Source: Adam Sadler, January 2011.

Section C

This section is mostly overgrown, however is generally accessible on foot. Sections of pavement with linemarking remain on the northern side of the freeway cutting and where this section meets the current alignment.

	Looking south towards the massive freeway cutting. Note the barbed wire fence and large rocks before you actually reach the freeway fence. The white line poking out from beneath the leaves was probably an edge line. Source: Adam Sadler, January 2011.
	Looking north from the same spot - the remnant pavement ends and the formation is overgrown beyond this point. Source: Adam Sadler, January 2011.
	Looking south towards the freeway. Note the rock cutting visible to the left - this section is cut into the side of the hill. Source: Adam Sadler, January 2011.
	A longer view south towards the freeway, showing the grass-covered formation. Source: Adam Sadler, January 2011.
	Looking north across an embankment. Source: Adam Sadler, January 2011.
	Looking south at the curve approaching the current alignment/northern end of Section C. Source: Adam Sadler, January 2011.
	A longer view south towards the curve. Source: Adam Sadler, January 2011.
	Two views of a section of remnant pavement where the old and new alignments meet, at the northern end of the Section C. Note the yellow centreline. Source: Adam Sadler, January 2011.
	Looking south along the deviation with Section C branching off to the right. Section D would have been to the left of the shot but is now fully overgrown. Photo taken: January 2011.

Section E

An access road to Boral's Gosford Quarries now uses this section of the old alignment. I am not entirely sure if the exact old highway alignment has been used, however in any case it is almost unrecognisable after being resurfaced.

	Looking south at the southern/western end of Section E. The road curving to the right is the new-build access road to the quarries; the highway would have gone straight ahead, slightly to the left, crossing what is now the freeway alignment. Photo taken: December 2008.
	Looking north on the old alignment showing the beginning of the large hairpin bend. Photo taken: December 2008.
	Looking south from the hairpin back towards the end of Section E. Photo taken: December 2008.
	Looking east through the hairpin. The old wooden guide posts mark the location of a culvert over Leask Creek. The old alignment has been modified beyond the creek - it would have continued to curve to the far right. Photo taken: December 2008.
	Looking west across Leask Creek. The road has been resurfaced, however the change in camber of the road offers a small clue as to where the alignment would have continued curving to the left. Photo taken: December 2008.

Section F

Adam Sadler discovered this section of remnant pavement and formation behind DEC's works depot. The position of the centre linemarkings, along with the longitudinal gap in the pavement, indicates that this curve had been widened on the inside at some point.

	The western end of Section F at the edge of the freeway - the wire fencing marks the boundary of the reservation. Source: Adam Sadler, November 2011.
	Steel rope fencing installed a few metres back from the previous photo - presumably an added piece of protection from when the old formation was still drivable. Source: Adam Sadler, November 2011.
	A westerly view of the overgrown formation showing how it is cut into the side of the hill. Source: Adam Sadler, November 2011.
	A clearer section of the old formation near the freeway. Source: Adam Sadler, November 2011.
	Emerging from the heavy overgrowth, this southerly view shows a section of remnant pavement still intact behind DEC's Girrakool works depot. The old alignment curves to the east. Source: Adam Sadler, November 2011.
	A closer view of the pavement, looking west towards the freeway. Note the divergence of the longitudinal joint in the pavement and the yellow centreline - this indicates that the original pavement has been widened on the inside of the curve. Source: Adam Sadler, November 2011.
	A wider westerly view towards the freeway. As you can see, this section of pavement is used as a storage area for the DEC works depot. Source: Adam Sadler, November 2011.
	Short and sweet - a view looking east from the same spot showing the end of the remnant pavement. The formation continues beyond the piles of wood but it is heavily overgrown. Source: Adam Sadler, November 2011.
	An easterly view of the overgrown formation - no more pavement to be seen. Source: Adam Sadler, November 2011.

Section G

Previously I had thought that between Section F and Section H there were no remnants of the old alignment. However, Daniel Thornton brought this little beauty to my attention when he spotted something over the edge of the bridge carrying the northbound freeway off-ramp at the Kariong Interchange. Upon further investigation it was discovered that it was the old low-level bridge across Piles Creek, located at the bottom of the valley, several metres below the freeway on and off ramps. It is understood that RMS continue to maintain this structure as a bridge asset.

	A westerly view from the northbound freeway off-ramp bridge showing the old low-level bridge over Piles Creek - almost buried but still there. The southbound freeway on-ramp can be seen high above the old bridge. Photo taken: January 2011 .
	A close up of the old low level bridge, taken from the northbound freeway off-ramp. It appears to be a steel girder structure, resting on concrete piers. Photo taken: March 2011.
	A close up view from the creek bed. Photo taken: January 2006 .

Section H

This short piece of remnant pavement wass located immediately east of what would have been the junction of Pacific Highway & Main Road No. 225 (Wisemans Ferry Road). Unfortunately it was destroyed in 2012 when a new commuter car park was built over the top of it.

	Looking southeast from Kangoo Road. Photo taken: January 2008.
	Another southeasterly view showing a single unbroken yellow centreline. The fence to the right restricts access to what appears to be a detention basin. Photo taken: January 2008.
	Looking northwest towards Kangoo Road. The junction with Wisemans Ferry Road would have been located approximately where the cars are in the background. Photo taken: January 2008.
	Another northwesterly view. Photo taken: January 2008.
	Looking southeast towards the end of the remnant pavement. You can just see the guard rail, marking the point where the new rejoins the old at the end of the deviation. Photo taken: January 2008.
	Closer view of the end of the remnant pavement. Photo taken: January 2008.
	Looking back from the end of the deviation, showing the new alignment branching off to the left. Photo taken: January 2008.
	A view of the deviation from a similar position to the photo above. This section was widened and resurfaced when the Kangoo Road intersection was signalised in 2005. Photo taken: January 2008.
	And the remnant pavement is no more - this view eastward from Kangoo Road shows the new commuter car park constructed in 2012. The access runs roughly on top of the old alignment. Source: Adam Sadler, July 2012.