The Ministry of Transportation says drivers should expect major delays on Highway 401 near Woodstock on Thursday and Friday nights.
Girders are being installed at the Highway 59 overpass on both nights. That means the 401 east- and westbound will be fully closed from 8 p.m. to 6 a.m. on Thursday.
On Friday night, the westbound lanes will be closed from 8 p.m. to 6 a.m.
"Highway 401 traffic will be rerouted via Highway 59 interchange ramps. Highway 59 will also be fully closed to traffic between Juliana Road and Old Stage Road in Woodstock on both nights," according to the Ministry of Transportation.
The closures were set to begin on Wednesday but wintry weather postponed the construction work until Thursday.