‘A tsunami of traffic chaos’: the new Sydney motorway prompting calls for a royal commission

Sydneysiders had been promised “nirvana” would be delivered by the $20bn WestConnex motorway so they are rightly bemused – if not bitter – about how they seem to have ended up in the other place.

The bungled opening of the final stage of WestConnex, the Rozelle interchange, is bad enough that veteran transport experts such as Michelle Zeibots at the University of Technology Sydney say only a royal commission can open the lid on how such debacles can happen.

Since the project opened on 19 November, morning drivers have headed into the city and found three lanes on two of the main arterial roads abruptly merging into one. Feeder streets from nearby suburbs were jammed, with movement slowing to barely one block an hour at the worst of the crunch times.

Zeibots says the cycle of costly toll roads that beget new bottlenecks, prompting yet more toll roads, must be broken,

Related: Westconnex: a $20bn money pit or a bold plan for Sydney’s future? Experts remain divided

Darcy Byrne, the mayor of Inner West Council, oversees a region that has endured a decade of dusty and noisy construction. He says Transport for New South Wales officials “were very concerned” in briefings three months ago about how WestConnex was going to perform.

“I think we can say after five days, it was as bad as anyone thought it could be,” Byrne said.

“We have warned for a very long time [that] when you tried to funnel such a greatly expanded amount of traffic into the same number of lanes at the Anzac Bridge at Victoria Road, it was going to be a tsunami of traffic chaos,” he said.

Infrastructure spending has lately been in the gun, with the federal government this month culling 50 projects, including 17 in NSW. It cited cost overruns and an inflationary pulse spawned by such a concentration of works as reasons for the move.

NSW’s roads minister, John Graham, warned in August that he couldn’t understand how the Coalition government had made promises that commuters would actually save time.

On Friday, his opposition counterpart, Natalie Ward, said Graham had been “heavily involved in getting the project ready, and now it’s all blown up and it’s someone else’s fault. Where is the accountability?”

This time the mess we’re in is so bad it justifies a royal commission to investigate how WestConnex came into existence

Michelle Zeibots

The premier, Chris Minns, said blaming the previous government for not doing the proper design work or resolving issues during their 12 years in office that ended in March was “not going to fix it. So we know we have to turn over every rock and speak to our engineers to try and get a solution as soon as possible for those that live in the inner west in Sydney.”

Moving back a bus lane to its original outer lane, improving signage or reducing morning truck movements may have temporary benefits and driver familiarity may also alleviate the past week’s mayhem.

But the government and motorway operator Transurban – who have a contract to run WestConnex until 2060 – say the traffic peak won’t come until February.

“If we’ve got a systemic or major design flaw then I can promise you the minister for roads [Graham] is looking at all options,” Minns said. Toll holidays is not among them.

Byrne and Zeibots say only a serious inquiry will reveal what went amiss.

“Until now, the whole history of WestConnex has been one of secrecy, in which data was never made publicly available,” Byrne said. That includes numbers used to justify it and how traffic flows have altered as each part of the project opened.

Related: Sydney commuters caught in 26km traffic jam after sprinkler test goes awry

Zeibots recalls the O’Farrell government coming to power in 2011 and commissioning a transport master plan. When it was completed, the plan “had every motorway in it that had ever been thought up since 1948”, she said.

“This time the mess we’re in is so bad it justifies a royal commission to investigate how WestConnex came into existence,” she said.

“We need to know who thought it up, who pushed for it, who in the private sector and public service designed, sanctioned and signed-off on its various stages and what the nature of the interaction was between government and private sector business interests.”

WestConnex now looks likely to compel a second harbour tunnel, the proposed Beaches motorway and another segment of the M6 tollway.

“It’s a cycle. It goes on and on and on, where they just build a new motorway,” Zeibots said. “You get induced traffic growth, it creates a new bottleneck, a new set of traffic jams, they are bigger and they are more difficult to contend with than the previous one.”

“What a private toll-road company is motivated by is completely and utterly anathema to what a city needs in order to have a good and adequate transport network to support its economic and social exchange functions,” she said.

Transurban declined to comment, referring questions to Transport for NSW.