The fate of the Cogswell Street Interchange in Halifax has been a source of debate for decades and now the city is calling for tenders on the demolition of the large, isolated section of downtown highway.

For 40 years the tangled concrete highways and overpasses of the Cogswell Interchange have dominated part of central Halifax.

The interchange was built in the 1970s as the centre piece of a highway project that would have seen much of Halifax's historic waterfront turned into a four-lane highway.

Public protest stopped the project and now the interchange's days are numbered. The city has called for proposals to rip down and redevelop the Cogswell lands.

Jen Powley, with the Ecology Action Centre, has lobbied to have the Cogswell Interchange redeveloped.

Jen Powley, with the Ecology Action Centre, said she would like to see the redevelopment take into account pedestrians, cyclists and affordable housing. (CBC)

"I'd like them to consider mobility, the Cogswell Street Interchange was built entirely for vehicles. We've moved past that, now we have to think about mobility and interconnectedness and how pedestrians and bicyclists can get across," said Powley.

"What I'd really like to see is affordable housing. Right now, living in the south end and downtown is doable if you're a high–class executive — if you're a secretary or a support worker or a clerk working at Park Lane, there's no way you can afford a house on the peninsula."

The city wants to see a mixed use for the land that could include roads, housing and green space. In 2009, council voted to get rid of the overpass.

A staff report at the time warned that maintenance costs would continue to climb while the benefits of keeping the interchange would continue to fall.

Already, the city has spent hundreds of thousands of dollars repairing the structure so it will hold up until it is redeveloped.

Powley said 2019 is the city's estimate of how long the bridge will last without needing further repairs, "but we know how good government estimates are, so maybe they should try and do something sooner."