Removal of the Melton Highway level crossing is half way to completion but a raft of traffic changes take effect next month as the next phase of construction begins.
Works began in the summer of 2016-17 to remove the level crossing at Sydenham by building a new six-lane road bridge over the Sunbury/Bendigo line.
Drivers, pedestrians and cyclists will take to three lanes on the southern side of the new road bridge starting from Wednesday while construction starts on the opposite side of the bridge.
There will be two temporary eastbound lanes and one westbound lane on the bridge.
Level Crossing Removal Authority project director Tony Hedley said that a recent traffic analysis found that reducing westbound traffic to one lane on the bridge would not significantly increase delays.
“We’ll switch traffic gradually over successive days and nights,” Mr Hedley said.
“Once cars are on the new bridge, we will close the dangerous and congested level crossing for good.
“When the road bridge is completed later this year, there will be a total of six lanes, three each way.”
During the next stage of works, westbound traffic will merge to one lane for about 200 metres between McCubbin Drive and Overton Lea Boulevard.
Pedestrians and cyclists will also be switched to the new shared path on the bridge to cross the rail lines safely.
Construction will be completed later this year.