Construction is about to start on a new Highway 400 overpass that will help alleviate traffic headaches in Barrie’s south end.

Mayor Jeff Lehman and city staff helped kick off construction of the $45-million Harvie Road/ Big Bay Point Road crossing on Wednesday morning.

"The missing link in many ways to unlock traffic is this bridge. So you don't have to go to Mapleview to get from west to east," Lehman says.

Harvie Road will be widened to five lanes between Veterans Drive and Bayview Drive. An estimated 20,000 vehicles are expected to cross it daily.

Lehman says it will also support the development of employment lands in the area.

"There is not a lot of road capacity servicing these lands so I think this is going to help a lot," he says.

Some construction has already started and eventually there will be some impact to traffic. In order to build the overpass, the connecting section of Fairview Road and Big Bay Point will have to be raised by 11 metres.

Fairview Road is expected to be closed for a period of five months from April to October in 2020.

The bridge is expected to be open to traffic by the fall of 2020.