The intersection between Bannister and Nicholson roads in Canning Vale was modified in February last year.
It is managed by the cities of Canning and Gosnells and was recently highlighted in the Canning Inquiry.
Mr Abetz said he agreed with the findings of the Inquiry that if the Canning Mayor and Council had accepted professional advice of staff, residents would have benefited from the road more than a year earlier.
‘When one considers the cost to families and businesses in longer travel times being endured for an extra year, it would amount to millions of dollars of lost productivity,’ he said.
‘I think the City of Gosnells did what they could ” they met with the City of Canning to impress on them the desirability of getting the City of Canning projects finished before the City of Gosnells started on the roundabout works.
‘But the Mayor of Canning and the councillors rejected this advice as well.’
Nicholson Road is one of the busiest roads in the southeast corridor of Metropolitan Perth, with more than 40,000 vehicles using it daily.
The intersection was classified as a black spot, being a high-risk area for accidents.
Upgrades to the intersection include a double right turn lane into Bannister Road for trucks and vehicles coming from Roe Highway.
There is also a dedicated left turn lane on Bannister Road from the railway line on Nicholson Road as well as a roundabout near Garden Street and Nicholson Road.
City of Canning chief executive Lyn Russell said the City acknowledged the findings of the Canning Inquiry.
‘Both City of Canning and City of Gosnells staff have always worked co-operatively on traffic issues and continue to have a very good relationship,’ she said.