New travel lanes coming to Washington Bridge to alleviate traffic. What to know.

The Rhode Island Department of Transportation has a plan to add an extra travel lane in each direction on the Washington Bridge to help ease congestion while the damaged westbound span is repaired.

Space for the new lanes on the compromised Interstate 195 bridge connecting the state's eastern and western portions – taking the total number of travel lanes from four to six – will come from narrowing the existing lanes on the single span now shared by drivers in both directions, RIDOT Director Peter Alviti Jr. said Wednesday at a State House news conference.

But it won't happen instantly.

New lanes may take 8 weeks to complete

Narrowing the lanes will involve construction and take an estimated eight weeks to complete, Alviti said, provided weather and the supply chains for things like concrete barriers and signs cooperate.

The new plan is intended to improve travel time on I-195 and to alleviate congestion while RIDOT comes up with and implements a solution to fix the westbound Washington Bridge span, which was closed abruptly in December when engineers discovered it was no longer structurally sound.

After a week of crushing traffic congestion with no westbound traffic able to cross the river on I-195 West, RIDOT opened the current bypass that allows both westbound and eastbound traffic to share the lanes on the eastbound span.

Exactly how much time adding another lane in each direction will save is guesswork.

"We know that adding 50% capacity to what is there right now is going to save considerable amount of time (for drivers), but depending upon the time of day and the traffic conditions, weather or accident conditions, that'll vary, right?" Alviti told reporters. "We do know that there will be an overall savings in both directions and that's what this is aimed toward."

How are the new lanes being built?

Space for the new lanes will come from narrowing the four 12-foot travel lanes to 10 feet and using the resulting space savings plus what are now the highway's shoulders to eke out two more lanes for travel.

The right lane in each direction will be 11 feet wide, and trucks will be confined to that lane, Alviti said.

To help prevent accidents, the speed limit on the bridge will be 40 mph.

By the time the additional lanes on the bridge open, RIDOT expects to learn what is at the heart of the problem with the westbound span and decide on a plan to fix it. That fix could range in scope from a targeted repair to a full tear-down and replacement.

In January, Alviti said a bridge-repair analysis and plan was expected by the "end of February or early March."

More: How did we get here? Lawmakers get their turn to question RIDOT about Washington Bridge

With the end of February now next week, he was able to provide no further details on that time frame Wednesday.

"As I said – I'll repeat myself – in late February or early March we'll be getting that information," he said. "We'll be making those decisions. You folks will know the minute that we do."

Alviti joined Gov. Dan McKee, Lt. Gov. Sabina Matos, Providence Mayor Brett Smiley and East Providence Mayor Roberto DaSilva and McKee's deputy chief of staff/bridge liaison Joseph Almond at the news conference.

This article originally appeared on The Providence Journal: New Washington Bridge/I-195 traffic pattern coming - what to know