Commonwealth Avenue Bridge Replacement to Cause Major Delays throughout Boston

By Beth Treffeisen

The Commonwealth Avenue Bridge replacement project to begin on July 26 2017 will have major impacts every single mode of transportation for commuters leaving or entering Boston from the west.

“It’s going to be highly impactful,” said James Kersten from MassDOT at a public meeting held on Tuesday, July 11. “It took years of planning and coordinating this project to get here today.”

Kersten said that this one location in the City is an integral bridge. The overpass is at a critical intersection that goes over both I-90 and commuter rail tracks.

Above, the overpass serves as a connection from Fenway to Cambridge over the Boston University Bridge, and is an important connector for those on MBTA Green Line B branch and key bus routes between Kenmore Square and Allston-Brighton.

“It impacts every type of transportation user in this one project,” said Kersten. “It’s very complicated.”

The bridge was originally constructed in 1965, and is structurally deficient. The concrete deck has deteriorated, and the steel beams are corroded.

The substructure was rehabilitated from 2014 to 2016 as a precursor to this project.

Conventional construction would take an estimated four to five years with substantial lane closures and reductions on I-90 and on Commonwealth Avenue.

This project will use Accelerated Bridge Construction (ABC) to replace the superstructure over two intensive construction windows: summer 2017 on the eastbound portion of the bridge and summer of 2018 on the westbound portion of the bridge.

During this summer, there will be an 18-and-a-half-day intensive closure window, which will have significant impacts to local and regional vehicular traffic and Green Line and commuter rail travelers.

The construction window will occur from July 26 to August 14.

This window was a carefully selected timeframe to minimize traffic impacts based on traffic volumes, MBTA ridership, Boston University summer break, and special events in the area.

The Massachusetts Department of Transportation (MassDOT), are reaching out to the public beforehand to allow commuters to decide on alternative routes in the area beforehand.

In addition, half of the bridge will remain open to emergency vehicles, MBTA bus routes, walkers and bikers. It will be closed to all personal vehicular traffic and Green Line T riders. A shuttle will replace service for Green Line riders for the duration of construction.

During Red Sox games and Fenway Park events, extra Green Line service will be added to the C Branch (Cleveland Circle) and the D Branch (Reservoir).

There will be police details along the route to progress bus traffic and answer pedestrian questions.

The bus detour for outbound and inbound Route 47 and CT2 that runs between the Fenway neighborhood and Cambridge, will run from the start of Beacon Street in Audubon Circle, follow Park Drive to St. Mary’s and go over the BU Bridge.

St. Mary’s in Audubon Circle that is currently a one-way street will be changed to two directions for buses only during construction for the detour.

Rob Devereaux the contractor of Walsh Construction said that there is going to be lots of signage so people know what’s going on and how they can get around it.

The project team is highly encouraging walking and will also partner with Hubway to provide additional bike service along Commonwealth Avenue.

“If you can stay away from the area, please do,” said Kersten from MassDOT. “We are asking that commuters shift from driving to walk and take a bike.”

The finished conditions will include new cycle track and bike accommodations, refinements in accessibility and pedestrian walkways, inclusion of floating bus islands, and refined landscaping and lighting elements.

On the weekend of June 3, the project team did a I-90 dry-run to test out restricting the lanes from four down to two in each direction. The project team learned valuable lessons on Friday night closure that enabled Saturday night to proceed smoothly.

I-90 impacts during the shutdown will include reduction to two lanes in both directions from 9pm on July 28 to 5am on August 7 (with additional lane closures during off-peak hours).

A traffic study concluded that if drivers continue normal patterns eastbound, the increase AM peak travel times from I-95 in Weston to I-93 in Boston from 24 to 35 minutes (47 percent increase) and increase PM travel times from 20 to 43 minutes (110 percent increase). Traveling westbound, the increase in travel time differed only in the morning from 15 to 22 minutes.

“If you do have to drive through I-90, pay attention, go slow (although I don’t think you will be moving fast anyhow), and keep off your phones,” said Kersten.

The I-90 Eastbound on-ramp from Cambridge Street/ Soldiers Field Road will be closed during this entire period and the I-90 Westbound Exit 20 off-ramp to Brighton/ Cambridge will also be closed intermittently during this timeframe.

“One of the biggest concerns we have is if there is an accident on I-90 during the construction period,” said Kersten. “There will be three tow trucks very close by and on call.”

The Commonwealth Avenue construction that is ongoing to revamp the curbside uses will be shut down while the bridge project is going on.

MassDOT said that they are working with both Google Maps and Waze about the impacts that the construction project will have. Kersten hopes that they will be able to divert cars way before the construction zone to help mitigate problems.

Real time traffic management system will be active during both shutdowns. Dial 511 before heading out onto the roadways and select a route to hear real time conditions. Follow MassDOT on Twitter @MassDOT to receive regular updates on road and traffic conditions.

Kersten said, “We’ve put a lot of thought in this and we think we have it covered.”

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