Vancouver city councillors have voted 5-4 to remove the Georgia and Dunsmuir viaducts, which connect the downtown core to neighbourhoods on the city's east side.

"This is a once-in-a-generation city-building opportunity," said Mayor Gregor Robertson in a written statement. 

"There is no decision at the city that has been more scrutinized, studied, deliberated or consulted on than whether or not to remove the viaducts, and after four years, it is time to move forward."

NPA councillors George Affleck, Melissa De Genova and Elizabeth Ball voted against the removal, as did Green Party Coun. Adriane Carr. 

Vision Vancouver councillors Andrea Reimer and Kerry Jang were absent. 

The vote on Monday night meant staff will start detailed planning and land negotiations, and will report back to council in 18 months with an update. 

The plan to remove the viaducts includes an increase in downtown park space. It also includes two new city blocks that would be used for social and market housing. 

Council members made the decision after hearing from dozens of speakers on the issue over several days, many of them concerned about how the removal would have an impact on traffic in the area.

Those who make use of the Cottonwood Community Garden were among the concerned speakers. The removal of the viaducts could impact the space, as the report said a road could be built where they currently stand.

At a previous meeting, Brian Jackson, the city's general manager of planning and development, had said it was a "critical time" to remove the viaducts, because the development of nearby land owned by Concord Pacific would only make the proposition more expensive.

He also said removing the viaducts would enable the city to create a better network of roads, which would connect neighbourhoods like Chinatown and Strathcona to the downtown core and the rest of False Creek. 

In June 2013, the city council voted unanimously to study the removal of the viaducts. Since then, city staff have been conducting traffic impact studies and community consultations to determine what impact the viaduct removals would have on the city.

The viaducts were originally built in 1971 as part of a larger proposed freeway through East Vancouver. That plan was scrapped after residents protested.

According to the city, they carry six per cent of all trips in and out of the downtown core.