Five kilometres of separated bike lanes will be built along St Kilda Road, protecting thousands of cyclists from motor traffic, if a VicRoads study finds their construction will not cause severe traffic congestion.

The lanes would be designed to transform St Kilda Road into the premier cycling route to and from the CBD from south of the city, and reduce injuries on what is the worst road in Melbourne for bicycle collisions involving car doors.

Bicycle Victoria chief executive Craig Richards on St Kilda Road. Credit:Eddie Jim

VicRoads is investigating how St Kilda Road traffic will be affected if the lanes are built between Linlithgow Avenue, just south of the Yarra River, and Carlisle Street in St Kilda - a distance of 5.2 kilometres. It is estimated the lanes would cost $12 million.

Options being considered include elevating the bicycle lane above other traffic and installing curbing between the bike lane and the rest of the road.