State transportation officials say it’s too early to tell what the effects of re-constructing the Neponset River Bridge are going to be on traffic. Construction started on the 40-year-old bridge, which connects Quincy and Dorchester, last week, leading to several lanes being shut down on bridge that sees 70,700 vehicles every day.

Ann Dufresne, a transportation department spokeswoman, said officials have not yet seen a need to alter their plan for lane closures. “That tells us so far so good,” she told the Reporter yesterday.

State Rep. Marty Walsh, whose district includes the Dorchester side of the bridge, said the bridge repairs are necessary and a “work in progress.” “If we survived the Big Dig for 13 years, we can certainly survive the Neponset Bridge construction.”

The plans call for the southbound right and left lane to be closed on Thursday and Friday, from 7 a.m. to 3:30 p.m., while the center lane is open to traffic. From 3:30 p.m. Thursday to 7 a.m. Friday, as well as the entire weekend, the southbound right lane will be closed, as will the Hancock St. off ramp’s right lane.

The $35 million project, part of a statewide bridge repair program, is expected to last three years. The time will be used to fix potholes on the bridge and replace its concrete deck, expansion joints, sidewalks, and lighting system. The project will also add handicapped accessible sidewalks and replace the stairs on the Quincy side.