Traffic is shifting on Route 91 as part of the ongoing rebuilding and resurfacing effort for the highway and its viaduct in downtown Springfield.
MassDOT is running traffic through the inner lanes of I-91 and closing a portion of the route, as well as exit 1-A and the Union Street on-ramp for re-paving activities.
The closures will be from 9 p.m. Thursday to 5 a.m.
Friday. Detours will be in place.