BOSTON — The carpool lane is opening along a busy section of Interstate 93 south to all traffic to help alleviate congestion caused by the Tobin Bridge project, but the move is drawing criticism from transit advocates.
The Tobin Bridge, a primary access point to Boston for those driving on Route 1, is seeing heavier-than-usual traffic backups as crews begin a two-year renovation of the aging landmark. Commuters have been finding alternative routes in and out of the city, which has increased traffic on Interstate 93 and other highways.
To help mitigate the congestion, the state Department of Transportation opened the high-occupancy lane between Medford and the Zakim Bridge in Boston to all motorists, regardless of how many people are riding in a vehicle. The agency said the switch is temporary and officials may "make adjustments as needed."
"MassDOT’s data indicates this may have a positive impact on the travel network during this major construction operation," Patrick Marvin, a spokesman for the agency, said in a statement.
But Chris Dempsey, director of the advocacy group Transportation for Massachusetts, said the move "penalizes carpoolers and bus riders" and "will worsen the situation for commuters."
"There's really no guarantee that opening up the HOV lane will reduce traffic congestion," he said. "And we believe it's important to encourage people to carpool and give them priority."
The 2.6-mile HOV lane north of the city is one of two sections of the highway designed to encourage carpooling during peak hours. The other is along a five-mile stretch of the Interstate 93/Southeast Expressway between Furnace Brook Parkway in Quincy and Morrissey Boulevard in Boston.
Travel in the HOV lane north of the city is usually restricted between 6 a.m. and 10 a.m. on weekdays. During those times, vehicles must have at least two occupants to use it.
On the Southeast Expressway, so-called "zipper lanes" shift for the morning and afternoon commutes, allowing HOV travel northbound from 5 a.m. to 10 a.m. and southbound between 3 p.m. and 8 p.m. on weekdays.
Because HOV lanes carry more passengers per hour than general-purpose highway lanes, they help with the state's dual goals of reducing greenhouse gas emissions from traffic and easing congestion, Dempsey noted.
Massachusetts is bound by a Supreme Judicial Court ruling that requires the state to meet a carbon emission reduction mandate of 25 percent below 1990 levels by 2020, and an 80 percent reduction by 2050. Roughly 45 percent of the state's carbon emissions come from the transportation sector — trucks and personal vehicles, according to the state.
State leaders are also wrestling with ideas to reduce congestion that earned Boston the dubious title of "most congested city" in 2018.
Sen. Barry Finegold, D-Andover, said state officials "need to explore every option" to alleviate commuter pains but questioned whether opening up the HOV lane will have an impact.
"Time will tell," he said. "It's getting tougher and tougher out there. We really need to do everything we can to reduce traffic congestion."
Finegold, who two decades ago led regional efforts to open the Interstate 93 breakdown lanes to Boston commuters, asked Transportation Secretary Stephanie Pollack to extend travel in the Interstate 93 breakdown lane by an hour each in the morning and evening as a short-term fix to ease congestion.
Breakdown lanes on Interstate 93 and other highways open as regular travel lanes — between Exit 41 near Andover and the New Hampshire line — from 6 a.m. to 10 a.m., and again from 3 p.m. until 7 p.m. Finegold had called for extending those hours to 5 a.m. to 10 a.m., then from 2 p.m. to 7 p.m.
But MassDOT said it would have had to extend the hours for all highway breakdown travel if it made the changes locally, Finegold said.
Sen. Diana DiZoglio, D-Methuen, said she while supports carpooling and efforts to reduce emissions, opening the HOV lane will help alleviate congestion.
"This is ultimately a temporary measure, one that may have a positive impact at a time when the Tobin Bridge construction is resulting in overwhelming traffic congestion," she said.
The bridge's two-year rehab will involve lane closures on the northbound and southbound sides.
Two of the three northbound and southbound travel lanes will be open during the day, and one of the three in each direction will be open overnight.
The MBTA is also encouraging people to use the commuter rail and offering free fares for inbound trips on the Silver Line 3, between Chelsea and South Station, as well as additional Blue Line capacity. Officials are also encouraging commuters to use the Haverhill or Newburyport/Rockport rail.
MassDOT said crews are using accelerated techniques to speed up the maintenance project, which is expected to be completed by 2021.
Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites.