Caltrans officials Tuesday changed their planned closure of Petaluma Boulevard South at Highway 101, with new closures set for Tuesday night and Thursday night, from 9 p.m. to 4 a.m.
Detour routes will vary, but signs will show motorists the way.
Petaluma Boulevard South was previously set to be closed for construction activity on Wednesday and Friday nights.
Nighttime closure of southbound lanes of Highway 101 at the Petaluma River Bridge and Petaluma Boulevard South is set to continue this week as Caltrans continues work on both the new bridge and the new interchange.
Southbound Highway 101 will be closed Wednesday and Thursday nights from 10 p.m. to 4 a.m. and Friday night from 11 p.m. to 5 a.m.
Southbound drivers will be sent on a 17-mile detour, exiting at Highway 116, turning left on the highway, and taking it to Highway 37, where they'll turn right to return to Highway 101.
A crane will be working over Petaluma River at the bridge Friday night, which will require brief closures of the river to boaters, Caltrans officials said.