Inner-west traffic predicted to worsen by up to 300pc

The traffic study, commissioned by the Inner West council, predicts hundreds of additional cars will crawl through local streets and arterial roads in order to access the WestConnex motorway or avoid it, once construction is completed.

According to the study, the worst-affected suburbs will be Haberfield and Ashfield, where traffic on at least four local roads will increase by more than 200 per cent by 2021.

Inner West mayor Darcy Byrne said the study showed that "the opening of stage one of WestConnex will result in the mother of all rat runs through suburbs like Ashfield and Haberfield".

"Thousands of Inner West residents will be forced to endure bumper-to-bumper traffic in their daily commute to work and when dropping their kids off to school," he said.

Topping the list is Martin Street, Haberfield, which is expected to be hit with a 320 per cent increase in traffic, as an extra 390 cars use the road in peak hour in travel connected with the motorway.

The $16.8 billion WestConnex motorway - a 33-kilometre toll-road project championed by the state government as "Australia's largest infrastructure project - has been highly controversial in the Inner West, where much of the construction has been concentrated.

By 2021, two key stages of the $33 billion project will be complete: the construction of the new M4 East tunnels between Homebush to Haberfield, and the new M5 tunnels from Kingsgrove to a new St Peters Interchange, both due to open to traffic by 2019.

The third stage of the motorway - tunnels linking the new M4 and M5 between Haberfield and St Peters - is expected to be finished by 2023.

Ken Welsh, the Inner West Council's strategic transport planner, said the council's study, which was produced by consulting firm Veitch Lister, was credible because it relied on traffic modelling used by the government's road infrastructure agency, the Roads and Maritime Services.

"We needed something the RMS would agree to and not challenge. Hopefully, by approaching it this way they will accept our findings."

He said the RMS modelling concentrated on the traffic flows from the motorway onto state roads, but there was little publicly available data on the anticipated impact on the local road network.

The council's study analysed traffic projections for 2021 and 2031 around each of the WestConnex entry and exit points, and "analysed every street in those precincts," he said.

The study found that by 2021, traffic along Barton Street in Haberfield would increase by 250 per cent, with an additional 490 vehicles expected to use the road during peak hour because of the motorway.

Similarly, traffic in Julia Street and Chandos Street, both in Ashfield, was expected to increase by 400 extra vehicles in peak hour.

"Some of that traffic is trying to get on or off the WestConnex tunnels," Mr Welsh said, adding that the 2021 modelling also took into account traffic trying to bypass construction activity while the final stage of motorway was built.

In 2031, eight years after the project's expected completion, some streets would still experience significant congestion in peak hour.

For example, an extra 300 vehicles were expected to use Northcote Street, Haberfield, while Waratah Street, also in Haberfield, would see a 50 per cent increase to 750 vehicles.

The RMS declined to comment directly on the study's findings, but a spokesman said the agency's modelling showed major roads would see significant decreases in traffic as a result of WestConnex.

"Daily heavy vehicle volumes on Parramatta Road and City West Link are forecast to drop by 40-50 per cent, and roads in the Inner West, such as Stanmore Road, Sydenham Road, Marrickville Road and King Street, are forecast to drop by 20-50 per cent," he said.

Additional modelling by RMS showed that by 2023 average travel speeds will increase by 10 per cent and distances travelled decrease by 12 per cent in the Inner West.