The eastbound Northern State Parkway between exits 37A and 40 will be shut down overnight five days a week beginning Monday, and the westbound parkway will be closed overnight beginning May 20, the state Department of Transportation said.
The full closures at the border of Nassau and Suffolk counties are so construction crews can perform work on the Round Swamp Road bridge, a department statement said.
The eastbound closures will be from 11 p.m. to 6 the following morning, Sunday nights through Thursday nights. Starting May 20, the westbound lanes will be closed from 10 p.m. to 5 the next morning, also on Sunday nights through Thursday nights. The closures generally will alternate directions weekly after May 20.
The closures are expected to last about three months. Electronic message signs will give drivers updates and additional information.
During eastbound closures, traffic will be diverted onto Exit 37A to the Long Island Expressway. Drivers can then take the LIE's Exit 49N onto northbound Route 110 to return to the Northern State Parkway.
During westbound closures, traffic will be detoured onto Exit 40 to take southbound Route 110 to the westbound LIE. Drivers can then get off on the LIE's Exit 46 to travel north on Sunnyside Boulevard to rejoin the Northern State Parkway.
No closures will take place the week of May 12 for the PGA Championship at Bethpage State Park in Farmingdale and during the Memorial Day and Independence Day weekends. Weather could also cause the cancellation, postponement or prolonging of work.
The bridge work will include excavating and installing steel sheeting, replacing the backwalls and installing new bearings.
The construction is part of a $9.5 million state project to improve safety and longevity on three Long Island bridges. The two other bridges are the State Route 107 bridge over Sea Cliff Avenue in Glen Cove and the Town of Oyster Bay, and the Route 110 bridge over Route 109 in the Town of Babylon, a department spokesman said.