BOSTON (CBS) -- With the Commonwealth Avenue Bridge replacement project starting Friday, MassDOT is warning residents and commuters about the transportation disruptions that will hit the city for the next three weeks.
Some 30,000 vehicles make their way up and down Commonwealth Avenue each day, but State Transportation Secretary Stephanie Pollack had a less-than-subtle message at a press conference for drivers Tuesday morning: "Stay away."
"If you don't need to be here, don't come anywhere near the area," she said. "Number two, if you have to go through it, have a plan ... This is really going to be disruptive to everyone who is on Commonwealth Avenue, on the Turnpike, uses the BU Bridge."
The bridge over the Massachusetts Turnpike will have its inbound section replaced in this part of the project, which has been in planning for the last five years.
"It was built more than 50 years ago, it's structurally deficient," Pollack said. "That doesn't mean it's going to fall down tomorrow, but it does mean that, in order to take good care of our infrastructure, we need to put in place a new bridge that is going to last for decades and make our infrastructure better."
Officials warned that, from cars to buses to trains, every mode of transportation in the area will be affected one way or another.
"This is gonna alter service on the Green Line, the Worcester-Framingham Commuter Rail line, and several of our bus routes," said Steve Poftak, MBTA Interrim General Manager.
Acting Highway Administrator Jonathan Gulliver said the project was "by far, the most disruptive project we're going to be doing this summer, and it is also one of the most disruptive projects that anybody can remember doing at the Highway Division in a very long time."
The accelerated method being used to construct the bridge involved building the bridge parts elsewhere. Those parts include 267 slabs of concrete and 44 steel girders which are laid out ahead of time in the order they'll be put together.
A large crane was already in place Tuesday to move those parts into place after part of the existing bridge structure is demolished.
Pollack said these methods are disruptive, but save years of work.
"While it will be a hellish three weeks, if we weren't using the accelerated bridge technique, it would be a hellish three or four or five years, so we should all be grateful," Pollack said.
Pollack acknowledged the mess the project will create, but said it's "short-term pain for long-term gain."
"There's a crane over there, it's large, it's red. I personally thought we should hang a giant sign from it that said 'Flee,' but, apparently, this violates the uniform manual of traffic control devices, so we're not going to do that," joked Pollack.
Commuters will start noticing the ripple effects of the project at 9 p.m. Wednesday, when the Green Line's B Branch will be replaced with shuttle buses between the Babcock Street and Blandford Street stops.
The T tracks over the bridge will be replaced as part of the project.
"If you take the Green Line or if you come over to Commonwealth Avenue here on Friday, there's not going to be any Green Line tracks," said Pollack.
Pedestrians and bicyclists will have full access across the Comm Ave Bridge on the westbound side throughout construction, and signs like the one below will assist passengers in figuring out their detours.
At 7 p.m. on Thursday, Commonwealth Avenue between Packard's Corner and Kenmore Square will be closed to traffic through 5 a.m. on Monday, August 14.
The biggest changes will be felt at 7 p.m. Friday night, when the Mass Pike lane restrictions take place.
"After 7 p.m. on weekdays and between 9 p.m. on Friday and 5 a.m. on Monday, alternating sides of I-90 will be reduced to one lane of travel in Boston," said Gulliver.
On the first weekend of the project, traffic inbound to city is being reduced to one lane, with outbound traffic restricted to two lanes. That will be flipped the next weekend, with inbound traffic restricted to two lanes and outbound to one lane.
Pollack said the MBTA Commuter Rail "might be a good alternative" for those who usually take the Mass Pike.
Earlier this month, Gulliver said commuters coming in from the west should expect "major, major delays" because of the lane restrictions, and said some computer models were showing that the bridge replacement could add more than 40 minutes to their commutes.
Officials conducted a weekend "dry run" of the lane closures back in June to try to find out how drivers would be impacted ahead of the start of the project.
MassDOT said this first leg of the bridge replacement should be finished by August 14.
More work on the project will be done next summer, with the outbound side of the bridge being replaced. A final phase will be completed in 2019.
The project is part of a much larger, $2.8 billion initiative by Gov. Charlie Baker's administration which includes the replacement of 80 other bridges, the laying of 160 miles of sidewalk, and the paving of thousands of miles of roadways across the Commonwealth.
WBZ NewsRadio 1030's Carl Stevens reports
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