If you’re one of the thousands of commuters who crosses the bridge carrying Park Avenue over railroad tracks while traveling east or west through Cranston each day, plan for lane shifts, closures and detours in the months ahead.

Activity has been underway at the 115-year-old, structurally deficient bridge in recent weeks, a reminder of the Rhode Island Department of Transportation’s long anticipated, $11.7 million project to replace it as part of the RhodeWorks program.

Now, the work is set to enter a new, more involved phase.

As of Tuesday, RIDOT planned to shift both lanes of travel into the eastbound lanes of the bridge, which runs over Amtrak’s Northeast Corridor between Elmwood and Willington avenues.

Then, in mid-May, the bridge will be fully closed for roughly four months to allow for its demolition and reconstruction.

Leading up to the closure, two-way traffic will be allowed during daytime and weekend hours. But some closures may be needed between the hours of 8 p.m. and 5 a.m. on Sunday through Thursday nights, according to the agency, as a “temporary utility bridge” is built. That structure must be completed before the demolition can proceed.

A detour utilizing Wellington and Elmwood avenues – estimated to add between six and 10 minutes to travel times – will be in place during the overnight closures and once the bridge is fully closed in May.

According to RIDOT, “traffic engineers will adjust traffic signal timings along the detour route to keep traffic moving as efficiently as possible.” A free RIPTA shuttle will also be provided once the bridge is fully closed.

An announcement of the traffic advisories outlines various measures RIDOT is taking “to replace this bridge in as short a timeframe as possible,” including an “early contractor involvement procurement method” – in which the contractor is “engaged early in the design process to identify the best solutions for construction prior to the start of work” – and the use of “pre-fabricated bridge units,” or PBUs, that are “installed side-by-side to rapidly create a new bridge deck, saving considerable time compared to the conventional approach of forming and pouring a concrete bridge deck.”

Combined, RIDOT estimates those steps will result in the project being finished three months earlier than expected.

The Park Avenue railroad bridge, which was built in 1906 and carries an estimated 15,000 vehicles a day, drew statewide attention in the summer of 2015 when it was temporarily closed for emergency repairs.

At that time, an inspection found “significant deterioration” in the wooden deck of the bridge, which had been last rehabilitated in 1991. The emergency closure also came during legislative debate over former Gov. Gina Raimondo’s proposed RhodeWorks program, which was signed into law months later.

The project is RIDOT’s latest in recent years involving bridges that carry Park Avenue over natural and man-made featured through the eastern and central part of the city.

In 2016, the agency performed repairs on the portion of Park Avenue that crosses Interstate 95. And last year, the bridge carrying the road over the Pocasset River near the Dyer Avenue intersection reopened after a months-long partial closure.

Updates on RIDOT’s schedule for the Park Avenue railroad bridge work will be provided at ridot.net/traveladvisories/#WestBay.