BOSTON — A carpool lane on Interstate 93 north of Boston, which has been open to general traffic for the past year, will again see restrictions under the threat of a lawsuit by environmentalists.
Beginning Monday, travel in the high-occupancy vehicle lane on I-93 southbound, between Medford and the Zakim Bridge in Boston, will be restricted to multi-passenger vehicles from 6 to 10 a.m. on weekdays.
During those times, vehicles must have at least two occupants in order to use the lane.
The state Department of Transportation said the move follows negotiations with the Conservation Law Foundation, which had threatened to take the state to court more than a year ago to stop the lane from opening to all commuters.
Staci Rubin, a CLF senior attorney, said reinstating the HOV lane will "drastically improve commute times" and "protect the health of overburdened communities" impacted by air pollution and traffic from commuters coming into the city.
While congestion on the highway has fallen dramatically since the coronavirus outbreak began last March, environmentalists say commuters will eventually return to offices in Boston, and the state needs to prepare.
"Now is the time to improve transit options and avoid the gridlock that plagued our region before the pandemic," Rubin said in a statement.
The 2.6-mile HOV lane north of the city is one of two sections of highway designed to encourage carpooling. The other is along a five-mile stretch of Southeast Expressway between Furnace Brook Parkway in Quincy and Morrissey Boulevard in Boston.
MassDOT opened the lane north of the city to alleviate traffic on the Tobin Bridge, a primary access point to Boston for those driving on Route 1, which is in the midst of a two-year renovation.
Prior to the pandemic, regular Route 1 commuters were finding alternative ways into and out of the city, increasing traffic on I-93 and other highways.
The Conservation Law Foundation threatened to sue, saying a change to the HOV lane rules violated the federal Clean Air Act and state environmental laws designating carpool lanes.
The sides have been negotiating for the past year in an attempt to reach a settlement.
As part of the agreement, MassDOT plans to implement other changes, including a pilot project allowing buses to travel on the Tobin Bridge and I-93 between Woburn and Somerville using a bus-only lane on the right-hand shoulder.
In a statement, Transportation Secretary and CEO Stephanie Pollack said MassDOT and the Conservation Law Foundation "share the objective of prioritizing the movement of people, rather than vehicles, on the commonwealth’s roadway network."
Christian M. Wade covers the Massachusetts Statehouse for The Salem News and its sister newspapers and websites. Email him at email@example.com.