Background
A 12.5 kilometre section of the F3 Freeway between Mount Colah and Cowan has beenwidened from four to six lanes. The project will improve traffic flow and road safety while reducing travel times.
There are now three travel lanes in both directions between Wahroonga and Kariong (approximately 43 kilometres) providing six lanes between Sydney and the Central Coast.
The $119 million project was jointly funded by the NSW and Australian governments.
The F3 Freeway between Sydney and Newcastle is part of the AusLink National Network. Approximately 65,000 motorists and 7000 freight vehicles travel daily between Sydney, the Central Coast and Newcastle.
Key features
- Widening of the freeway from two lanes in each direction to three lanes in each direction.
- Additional lanes built within the median area of the existing F3 Freeway.
- Upgrading of stormwater drainage.
- A road design that complements the local environment.
Benefits
- Improved road safety by removing the need to merge from three lanes to two lanes.
- Improved road safety through providing a smoother, more durable road surface and improving drainage for road water run-off.
- Improved surface life of the pavement and reduced traffic noise by treating some sections of the freeway with a diamond grinding process.
The works
F3 Freeway widening and road maintenance work between Wahroonga and Cowan was undertaken in four sections.
Section 1: Berowra ramps to Cowan (3.4km)
Start: December 2006
Complete: September 2008
Features: Three lanes in each direction.
Open grade asphalt surface replaced the previous asphalt surface, on top of a crushed rock base. Open grade asphalt selected for drainage reasons.
Section 2: Mount Ku-ring-gai to Berowra ramps (4.9km)
Start: March 2008
Complete: September 2009
Features: Three lanes in each direction.
New concrete lanes treated with diamond grinding process to ensure the old and new sections are the exact same surface level.
Section 3: Mount Colah to Mount Ku-ring-gai (4.2km)
Start: September 2008
Complete: November 2009
Features: Three lanes in each direction.
All lanes treated with diamond grinding process to prolong pavement life and to reduce noise.
Section 4: Wahroonga to Mount Colah (5km)
Start: September 2008
Complete: November 2009
October 2008 - Removal of deteriorated asphalt layer from northbound lanes completed.
March 2009 - Diamond grinding trial on concrete surface.
May 2009 - Asphalt resurfacing works commenced but put on hold until warmer weather.
September 2009 - works recommenced.
November 2009 - resurfacing complete.
Features: Northbound lanes of freeway resurfaced with low noise asphalt following a less than expected reduction of noise levels after diamond grinding trial.
Traffic noise - Mount Colah to Cowan
Approximately two months after completion of the F3 Freeway widening work, noise levels will be measured. If the noise criteria have not been achieved, the RTA will investigate potential treatments to decrease noise, either by treating the freeway or residential properties.
Click here for a fact sheet that explains:
- Road conditions on the F3 Freeway in the Hornsby Shire area.
- Recent maintenance work.
- Current traffic noise.
- A pilot project to reduce noise levels (diamond grinding trial).
Traffic arrangements
With the completion of construction works, the speed limit has been raised back to 110km/h.
Should road and traffic conditions change, motorists will be updated via variable message signs/variable speed signs on the freeway.
Section 4: Diamond grinding trial and traffic noise, Wahroonga to Mount Ku-Ring-Gai
The RTA removed the deteriorated asphalt surface in September/October 2008.
In March 2009 the RTA conducted a trial of the diamond grinding technology to see if there was a large difference in noise levels after the grinding process. This was the first time this technology was used in Australia.
The trial showed noise levels reduced by only one to two decibels. This reduction did not meet the RTA’s expectations. Local residents are likely to be experiencing similar noise levels as they had before the trial.
The RTA has concluded that further investigation would be required before considering diamond grinding to reduce traffic noise.
The diamond grinding process should still be considered in making the road smoother and more durable, and reducing the risk of road crashes from skidding or hydroplaning on water on the road.
For more information on the diamond grinding trial, a question and answer sheet and a copy of the noise monitoring report is available here.
Road maintenance – asphalt works
As the anticipated noise reduction was not achieved in Wahroonga the RTA installed low noise asphalt surface on the F3 Freeway in the Wahroonga / Asquith area on the northbound lanes.
This should achieve a noise reduction for residents.
As part of the resurfacing work, the RTA also provided a truck parking facility on the F3 Freeway northbound at Wahroonga, underneath the Pacific Highway interchange road bridge.
The purpose of this facility is to provide an area that allows trucks to park safely, check their loads, and then safely merge into the F3 Freeway traffic to continue their journey. It is expected that trucks using this facility will rejoin the freeway within a very short time.
For further information on the road resurfacing works, an information sheet is provided here.
Contact information
For noise-related enquiries regarding F3 Freeway widening work between Mount Ku-ring-gai and Cowan, please contact RTA project manager, Iain MacLeod, on 02 9352 9526 or email CC_Sydney_Region@rta.nsw.gov.au
For noise-related enquiries regarding F3 Freeway maintenance work between Wahroonga to Mount Ku-ring-gai), please contact RTA project manager, Neil Forrest, on 02 8849 2933 or email CC_Sydney_Region@rta.nsw.gov.au
F3 Freeway emergency traffic management plan
For further information on emergency traffic management planning click here.
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