The southbound lanes of the South Grand Island bridge will be closed between 8 p.m. and 6 a.m. Sunday through Thursday nights starting Sunday and running through October, the New York Thruway Authority announced Friday.

During the scheduled construction hours, all southbound traffic will be diverted to a single lane on the northbound South Grand Island Bridge, officials said. Motorists should heed the overhead lane designation signals when traveling in the area.

The project is the final phase of a two-year, $14 million rehabilitation contract. This year’s work includes deck joint repairs, a new overlay for the driving surface and the installation of a movable barrier gate at the south approach of the south bridges.

The south bridges to and from Grand Island carry more than 80,000 vehicles every day between March and October.