Work on the bridge that will replace the Petitcodiac causeway between Moncton and Riverview is expected to get underway at the end of May, and residents are being warned to expect traffic delays.

Riverview Mayor Ann Seamans said she doesn't want people to be surprised when construction begins.

"We want to get the word out there and remind people this is coming up," Seamans told Information Morning Moncton.

About 25,000 vehicles cross the causeway each day.

This is the third phase of the project, which will see the causeway replaced with a 240-metre steel girder bridge, at a cost of $61.6 million.

"At the end of May they'll be doing the actual detour and then in June, that's when the actual work will start on the bridge itself," Seamans said.

The causeway is four lanes and the detour will only be two, so significant congestion is expected.

"There definitely will be an impact — that's for sure," Seamans said.

Work to continue in winter

Seamans and members of Riverview town council have been meeting regularly with provincial officials.

A spokesperson for the Department of Transportation told CBC News the manager of the Petitcodiac River Bridge project won't be available for an interview about the construction plans until May 1.

In an email, however, communications officer Jeff Hull said the two-lane detour will begin on the Riverview side of the causeway. It will be paved and about 850 metres in length.

"When approaching Moncton from Riverview, traffic will transition into two lanes at the gate structure and continue with a two-lane configuration until the end of the detour," he said.

"Traffic will transition to the additional existing lane at that point and continue into the traffic circle in Moncton."

Hull said the detour will be built over the next six to eight weeks and then will be open to traffic.

"The work area for the bridge structure will then be isolated and protected to start work on the footings and the substructure of the bridge."

Construction is expected to continue through the winter.

Total closure of causeway coming

Seamans said she is waiting for a detailed schedule of the work that begins soon, but in the meantime she is most worried about plans to completely close the causeway to traffic for four to six months.

"The biggest concern of council over this period of time is the total closure, which they're talking about in 2020," she said. "So we have to work very closely with the province to make sure there's as little an impact as possible and the closure is as short as possible.

"Coverdale Road is a busy road and all of that traffic having to go across the [Gunningsville] Bridge ... that is our biggest concern."

Seamans said she's been told the total closure of the causeway in 2020 is necessary for safety reasons, but she is hoping the engineers will be able to find a way around it.

"We're working with the province regularly to see if they can't minimize that time so that it wouldn't have to be a full closure at all because there is a safety concern with only having one crossing to get to the hospitals."