Sagtikos State Parkway

Limited access parkway in Suffolk County
Past the exit, the Sagtikos State Parkway crosses under CR 13 and immediately reaches the Sagtikos Interchange at exit S1 – a large, modified cloverleaf interchange with the Long Island Expressway (Interstate 495). The junction brings the parkway into the Town of Smithtown, where it bends northwestward and parallels CR 67 (Vanderbilt Motor Parkway) for a half mile (0.8 km) through the town's Commack section. CR 67 eventually turns westward to pass over the Sagtikos Parkway, at which point the parkway curves back to the north and enters exit SM1E, a cloverleaf interchange serving as the Northern State Parkway's exit 44. The Sagtikos State Parkway name ends here while the highway continues northward toward Long Island's North Shore as the Sunken Meadow State Parkway. In addition to this donation, James Fisher, a nearby resident, gave the commission of land north of the Gardiner property and another north of the Fisher property to ensure that LISPC had the necessary right of way for the new parkway. The right of way on which the parkway was built had originally been part of a private road leading to Sagtikos Manor. The parkway was designed to have connections with the Sunken Meadow Spur (the future Sunken Meadow State Parkway) and the Captree State Parkway (now known as the Robert Moses Causeway) proposed by New York City urban planner Robert Moses. On November 13, 1949, a new interchange between the Southern State Parkway and Bay Shore Road was opened to traffic. This interchange would eventually serve as the Southern State Parkway's junction with the Sagtikos, Heckscher and Captree state parkways. Proposals conceived at this time called for grading on the new Sagtikos State Parkway to begin in early 1950. In March 1950, $3 million (1950 USD) was earmarked out of a $104.5 million budget for the start of construction on the parkway. The contract for paving 4.76 mile (8 km) of the Sagtikos Parkway was awarded by the New York State Department of Public Works on June 7, 1951, to Hudson Contracting Corporation of Kew Gardens, who entered a bid of $1,407,037 (1951 USD) for the project. The remainder of the parkway was paved as part of a contract valued around $418,000 (1951 USD) and let by the state on July 11. A 3 mile (5 km) stretch of the Northern State Parkway was also built as part of the project. On September 29, 1952, an extension of the Northern State Parkway, Southern State Parkway, and the entire length of the Sagtikos State Parkway were opened without celebration. Robert Moses commented that the completed parkway reflected LISPC's objective to construct well designed recreational facilities.

From 1997–2001, engineers from NYSDOT worked on a $6.5 million (2001 USD) study aimed to improve Long Island's transportation system by 2020. The resulting plan included proposals to widen 130 mile (209 km) of roads, including the entirety of the Sagtikos State Parkway – from the Southern State Parkway to the Northern State Parkway. In 2002, the Wolkoffs, a family of real estate developers, bought land used by the Pilgrim Psychiatric Center for $20 million (2002 USD) with the intent of redeveloping the property as a new smart growth community named Heartland Town Square. The community, situated near the interchange between the Sagtikos Parkway and the Long Island Expressway (I 495), would have 9,000 housing units and various commercial & recreational buildings. As part of the redevelopment of the property, a study was done on the existing facilities and the surrounding area, which noted several deficiencies in the area's transportation system – including several related to the Sagtikos. The study determined that the deficiencies would be "exacerbated" if no changes were made. In response, the study suggested that a third lane be constructed along the Sagtikos from the Southern State Parkway to the Long Island Expressway. The bridges over the Sagtikos at Campus Road and Crooked Hill Road (CR 13) would have to be reconstructed to make room for the added lane, and the interchange with Pine Aire Drive (exit S3) would be completely rebuilt. A new interchange would also be constructed on the parkway between Pine Aire Drive and Campus Road, creating a junction with CR 100. Gerald Wolkoff thought that the discrepancy stemmed from his belief that transportation should be funded by the government, not from private sources, as his project would generate tax revenue for the government.