There is more traffic upheaval in Northbridge with the start of work to convert Beaufort Street back to a two-way road.
The project, due to be completed by April 7, will bring back bus priority lanes that will operate at peak times.
According to the City of Perth, the reintroduction of two-way traffic flow from Wellington to Newcastle streets was designed to "improve the legibility and permeability of the local road network".
The council hopes to achieve this with two-way traffic in Beaufort and William streets.
Lord Mayor Lisa Scaffidi said the plan was about more than just traffic flows.
"It's also about the movement of people in and around our city, improving the connectivity between existing streets and making it easier to navigate city streets," she said. "We want to make the city a destination rather than a thoroughfare.
"Two-way traffic flow will create a more user-friendly and accessible environment for all road users.
"Our priority is pedestrians, public transport and then cars.
"The concept of one-way streets is outdated urban thinking. Two-way flow will make people feel safer and more inclined to stop and visit city stores and attractions.
"Two-way streets will reduce journey times for drivers and are safer for pedestrians because they lower vehicle speeds."
The priority bus lanes will operate from 6.30am to 9am (southbound) and 4pm to 6.30pm (northbound). Outside these times, the lanes will be used for parking.
When the work is complete, Beaufort Street buses - routes 21, 22, 67 and 68 - will run in both directions. Currently, they use Brisbane and William streets to enter the city.
A spokesman for the Public Transport Authority said other bus routes, including William Street services 16 and 60 and Lord Street services 41, 42, 43, 48 and 55, would also use Beaufort Street to enter the city when the two-way work was finished.
Ms Scaffidi said the new routes would better link city streets.
The two-way project was endorsed by the council late last year after discussions with the City of Vincent, the Department of Transport, Main Roads WA and the PTA.