A damning report into a trouble-plagued underground motorway interchange has found the Sydney project prioritised "financially motivated" design over public interest.
A NSW parliamentary inquiry into the $3.9 billion Rozelle Interchange - the most complex below-ground road junction in the nation - was launched in February following the traffic chaos caused by its opening.
The backlash against the interchange also led to the inquiry recommending that there should be no further privatisation of NSW roads.
The so-called spaghetti junction, started under the former coalition government, has been criticised for blowing out morning commute times and worsening traffic in surrounding inner western suburbs.
The report from a Greens and Labor-dominated committee on Monday found the project suffered due to the financial model of the adjoining WestConnex motorway, based on maximising its sale value.
Design decisions for the interchange were made to funnel more cars through the motorway, increasing the volume of tolled trips and the project's ultimate sale price, it found.
Westconnex is owned by private toll-road operator Transurban after a $20.4 billion sale completed in 2021 under the former coalition government; a move opposed by the then-Labor opposition.
"This (process) ultimately led to design decisions that were financially motivated and made at the expense of community interests," the inquiry declared.
Other findings included an unacceptable lack of transparency around design decisions and a concerning absence of clarity on the deal between the government and Transurban.
The report also highlighted communities impacted by the interchange were promised benefits that were not realised.
Greens MP and inquiry chair Cate Faehrmann said it was clear the interchange was not built in the interests of the local community.
"'Many witnesses expressed frustration that public transport options were not genuinely considered as alternatives to Rozelle Interchange and the broader WestConnex project," she said.
Liberal MP Natalie Ward, a roads minister in the Perrottet government, conceded in the report that the "opening of the Rozelle Interchange was clearly sub-optimal for drivers and the local community".
But in a dissenting statement she said the benefits of the project were "already being realised", citing less traffic across key arterial routes and the enabling of other public transport infrastructure projects.
Premier Chris Minns said the state had "well and truly learned its lesson" about the privatisation of toll roads, a practice his government had committed to ending.
"We're determined that when we pursue major changes, the public are aware of how it will affect their community," he said, adding that projects should take into consideration any intended and unintended consequences.
Transurban said the interchange had meant less time in traffic for motorists into the city, including commutes up to 30 minutes shorter for those driving from Penrith.
"We acknowledge the congestion issues that have occurred on the surrounding road network and appreciate the frustration of the local community," a company spokesperson said in a statement.
