OPINION: Concerns over new Coramba Interchange design on the Coffs Harbour Bypass

DEAR News Of The Area,

AS a member of the Coffs Bypass Community Consultative Committee (CCC) representing the Coffs Bypass Action Group (CBAG) I wish to bring to the communities attention, especially those living in the west Coffs basin, proposed changes to the Coramba Interchange made by Ferrovial Gamuda, the bypass builders.

The community was asked to give feedback to the design changes by 20 February after the January 23 update announcement, and to date, no reply to my submission outlining concerns has been received.

To have such a big design change from the Environmental Impact Statement design, which we were led to believe was the design since 2019, at the last minute is unsettling.

Surely Transport for NSW engineers who have been working on designs for the bypass for many years could not have got it so wrong that such massive change in design is warranted.

If such a big change in position was necessary, perhaps consideration could have been given to putting the interchange to the west of Coramba road well away from housing rather than further north.

Please check the old simple design against the “spaghetti” version currently planned.

In the old design, if you wish to go south from Coramba Rd, it was a simple left hand turn.

In the new design, it will be necessary to travel right firstly up a 4.7 percent ramp, turn a sharp left then go back down again.

Double the vehicle noise and pollution for the closest communities.

The Joint Venture builders should consider the community being affected when the interchange and bypass is operational, not just for their ease of construction as this design change appears to be.

A little known fact is that Arcadis, another international design and consultancy company, was confirmed as the lead designer for the Ferrovial Gamuda Joint Venture.

Part of their solutions is “a pavement design that adopts asphalt with an innovative binder to increase stiffness and fatigue resistance” and I hope this equates to a low noise asphalt being used along the bypass as per a condition of construction approval along with tunnels.

Worrying concerns:

The new interchange will be approximately 360m north of the EIS design not 200m as stated on Transport NSW brochures which is very misleading.

Whilst the new design is slightly further away from homes, it is now 2m higher than the old design, and combined with the distance further north, it appears the interchange will be more visually intrusive to the homes in the hilly terrain in the west Coffs basin.

The most important factor from the new interchange design relates to noise issues for the area in the vastly increased gradient of the south bound on ramp.

This has increased from one percent in the old design to 4.7 percent in the new which is over the desirable percentage gradient.

This increase in gradient, combined with an extra lane of traffic going south compared to the old design, will cause a huge increase in traffic noise volume.

The road design for the Coramba Interchange will accommodate B Double trucks – 26m.

Where are these vehicles going?

Everyone knows that the road from the interchange into the CBD along West High Street is a nightmare already.

There are a projected 1100 vehicles, up from 600 in the EIS, per day extra which will come off the new interchange which will have to disperse into Coffs.

The new noise report for this change of design is apparently not due out till possibly August and work should not commence on the Coramba Interchange until received. There are possibly a number of homes extra that will require noise remediation.

The western sun setting also needs to be taken into consideration for road safety with the loop design as anyone who has driven home to the west in the late afternoon knows how blinding the sun is.

The design speed of 110kph around the Coffs basin also needs to be reassessed by Transport as the route is very close to many homes.

A lower speed would be a simple remedy for Transport to help meet the noise level issue as required by the Department of Planning and Environment.

A lower speed of 80kph on the Coffs bypass will have a minimal effect on time taken but will have an enormous beneficial disruptive noise outcome for the newly affected communities along the route.

Ask any resident from the northern suburbs what the noise was like when the speed limit was increased from 80km to 110km and reports to this day say the increase in volume was unacceptable.

We need the bypass built, but let’s try to get the best possible outcome for the community most adversely affected by the project along the whole new route.

Coffs Bypass Action Group,
Coffs Harbour Bypass Community Consultative Committee member.

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