State officials are warning drivers who normally use the Callahan Tunnel to expect a longer commute starting on Monday, which will bring the first workday rush hour traffic since a three-month closure of the busy tunnel began late Friday night.
The Lieutenant William F. Callahan Jr. Tunnel, which carries an average of 30,000 vehicles daily northbound from the North End to Logan International Airport and Route 1A in East Boston, is scheduled to remain closed for reconstruction until March 12.
Drivers will be rerouted to one of three routes: the Ted Williams Tunnel, the Tobin Bridge, or Route 16 east to Route 1A south.
“There will be an adjustment period for the motoring public,” said Sara Lavoie, a spokeswoman for the Massachusetts Department of Transportation. “We ask that they become familiar with all detour routes on our website or choose public transit. Allowing extra time for your commute would be wise, especially leaving Boston in the afternoon.”
She said that on Saturday and Sunday evenings there were reports of heavy traffic on one of the main detour routes: eastbound in the Ted Williams Tunnel. Otherwise, the Callahan Tunnel’s closure did not seem to cause any significant traffic issues or other problems over the weekend.
“Overall, we are pleased with how traffic has flowed,” said Lavoie. “But, we realize this is a weekend period with light volume.”
“The first Monday commute comes during a popular vacation week. This will allow us to monitor and adjust before the full volume of vehicles returns from the holidays,” Lavoie said.
Tweaks have already been made. Some signs were covered over the weekend “to make the detours as clear as possible,” she said.
The Callahan project, expected to cost about $35 million, will include installing a new deck, curbing, and wall panels inside the 52-year-old tunnel.
To help reduce congestion during construction, the state has lifted commercial vehicle-only restrictions for eastbound traffic on the South Boston Bypass Road.
Some high-occupancy vehicle-only lane restrictions have also been lifted. Electronic message boards in the area will use real-time traffic data, to suggest the fastest detour route at the time.
And, the MBTA will increase some service on the Blue and Silver lines.
Matt Rocheleau can be reached at matthew.rocheleau @globe.com.