Cars can queue up to 260m during the afternoon trying to turn right on to Nicholson Road, Main Roads WA and City of Gosnells investigations showed.
The intersection connects drivers to a key Canning River crossing, and services Canning Vale, Langford, Maddington and Kenwick commercial areas.
The City and Main Roads analysis showed the intersection serviced high traffic volumes at rush hour but the right turn on to Nicholson Road was the worst.
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READ NOWA City report said this meant unreliable journey times, driver frustration and stop-start conditions that increased crash risks.
The report was in response to Public Transport Authority (PTA) investigations that found the eight bus routes using the right turn were experiencing long delays.
It approached the City of Gosnells proposing to convert one of the highway’s southbound lanes to a 24-hour bus-only turning lane just before the lights, and widen Nicholson Road to continue the bus lane for about 200m before merging into traffic.
City staff warned that this alone would not improve car users’ experiences much.
They reported that Perth’s urban sprawl meant many people had no option but to rely on cars, particularly in the commercial and industrial areas surrounding the intersection.
Chief executive Ian Cowie said the PTA plan had supplanted an upgrade option that Main Roads had prepared and it supported, but the bus lane was the highest immediate priority.
The City approved the PTA changes on condition that they be reviewed regularly and not impede further works at the spot in future.
‘Monitoring will determine the need for any further changes,’ he said.
PTA spokesman David Hynes said the works benefited the whole community as each bus carried up to 100 passengers.
He said the intersection was just one of the spots earmarked for upgrade under the Bus Priority Program Partnership.
‘The majority of drawings have been completed and have been sent out to stakeholders for comment,’ he said.
Car insurer AAMI listed Albany Highway in Cannington the worst accident hotspot in Perth for 2013.