Caltrans has scheduled closures for southbound Highway 101 in Petaluma.

Southbound Highway 101 will be closed at the Petaluma River Bridge tonight from midnight to 4 a.m. and Sept. 19 from 11 p.m. to 6 a.m.

Detour: Exit at Highway 116/Lakeville Highway and turn left. Continue to Highway 37 and turn right. Continue to southbound Highway 101. Motorists should expect travel delay and allow extra time to reach their destination, Caltrans said.

Petaluma Boulevard South under the Petaluma Bridge will remain open during the southbound U.S. 101 closure.