Bookmark and Share

This 2018 photo shows the twin-span Robert Moses Causeway bridge heading south over Great South Bay. The two-lane southbound span opened in 1954 and was rebuilt in the late 1990s. The three-lane northbound span to the left opened in 1968. (Photo by Steve Anderson.)


NYSDOT Reference Route:

8.1 miles (13.1 kilometers)
(parallel Great South Bay span built 1966-1968)

Passenger cars only north of EXIT RM1 (NY 27 / Sunrise Highway).
Height restrictions apply.

THE CAPTREE PARKWAY AND CAUSEWAY: The Robert Moses Causeway, which was known as the Captree State Parkway until 1963, forms part of the north-south parkway corridor from Sunken Meadow State Park in Kings Park to Robert Moses State Park at the western tip of Fire Island.

Opposition to the "Captree Causeway" appeared soon after it was first proposed by Long Island State Parks commissioner Robert Moses in 1930. At that time, The Bay Shore Sentinel-Journal ran an advertisement from a South Shore citizens' group (led by mustard magnate Frank Gulden) opposing the causeway over Great South Bay as follows:

The State of New York proposes to build at great expense with our taxpayers' money, a sprawling trestle between West Islip and Captree Island, across the most beautiful part of Great South Bay - 3 miles of elevated roadway 30 feet high - directly across this great bay that has made our communities famous for their natural beauty. Shall the famous beauty of our Great South Bay be destroyed? Shall our shores be cluttered with noisy, fume-spreading, transient automobile traffic?

In the years since, Moses befriended Gulden, who became a proponent of Long Island's park and parkway system. While Gulden lent his support, work on the Captree State Parkway and Causeway waited until the postwar era.

The first section of the Robert Moses Causeway, between the Southern State Parkway and EXIT RM2 (NY 27A / Montauk Highway) in West Islip, was completed in 1953. The original construction of the parkway comprised of two 22-foot-wide roadways, each carrying two lanes of traffic, with the opposing roadways separated by a nine-foot-wide grass median.

The first causeway bridge, which had one northbound and one southbound lane, was opened to traffic in April 1954. The two-mile long span across Great South Bay to Captree Island features a 600-foot-long main span, with a 60-foot clearance for boats. On either side of the main steel-arch span, a series of piles support the roadway 25 feet above Great South Bay. The piles are arranged not only vertically, but also diagonally. The diagonal piles, which are called "batter piles," resist the forces along the roadway such as those caused by vehicles stopping or starting, as well as those caused by the expansion and contraction of the bridge deck due to temperature changes.

At the southern terminus of the Great South Bay span, the Robert Moses Causeway continues south through Captree Island, where an interchange is provided for local traffic. After crossing the State Boat Channel over a 665-foot-long bascule bridge, the causeway meets the Ocean Parkway at a cloverleaf interchange. This interchange, which provides access to Captree State Park, Gilgo State Park, and Jones Beach State Park, served as the southern terminus of the Robert Moses Causeway until 1964.

The Fire Island Bridge continues the two-lane road, one lane in each direction, across Fire Island Inlet to its terminus at Robert Moses State Park. When first proposed in 1938, the span was to be a vertical-lift span with a design similar to that of the Marine Parkway-Gil Hodges Memorial Bridge. Later, the design of the Fire Island Bridge was changed to conform with that of the Great South Bay span: a 600-foot steel-arch span with a 60-foot clearance, flanked to the north and south by low-level causeway approaches. This final link of the Robert Moses Causeway opened in 1964.

LEFT: Robert Moses observing construction of the single-span causeway bridge that bears his name over Fire Island Inlet, just before the bridge's completion in 1964. (Photo by New York State Division of Parks, Recreation and Historic Preservation.) RIGHT: The completed two-lane causeway leading to the water tower at Robert Moses State Park on Fire Island. (Postcard supplied by John Delin and Pamela Boslet Buskin.)

ADDING CAPACITY ACROSS GREAT SOUTH BAY: The popularity of Robert Moses, Captree and Gilgo state parks seriously tested the traffic capacity of the original two-lane bridge and roadway. Southbound traffic to the beaches was backed up for miles in the morning, while northbound traffic to Long Island was heaviest in the late afternoon hours. To meet this demand, a parallel causeway was constructed over Great South Bay just east of the existing two-lane causeway.

To accommodate the peak travel hours of the beach-going public who tend to arrive over several hours of the morning, but depart in a noticeably shorter period in the late afternoon, the new bridges and roadway for northbound traffic were constructed three lanes wide. Along Captree Island, the opposing roadways were separated by a wide, variable median. The original two-lane roadway became the southbound lanes of the causeway. The three-lane parallel Great South Bay span, which was to carry the northbound lanes, was constructed between 1966 and 1968.

DESIGN CHANGES: In 1977, maintenance of the Robert Moses Causeway was transferred from the Long Island State Park Commission (LISPC) to the New York State Department of Transportation (NYSDOT), although ownership remained under the jurisdiction of the New York State Office of Parks, Recreation and Historic Preservation (NYSOPRHP). To accommodate the increase in traffic volume and speed, and to address the accident history, the NYSDOT began to modify the parkway in accordance with Federal and state traffic safety guidelines.

In 1978, one year after maintenance of the parkway was transferred from the LISPC to the NYSDOT, the southbound tollbooths prior to the Great South Bay bridges were removed. For about a quarter-century, a 25-cent toll was collected at that location.

During the late 1980s and early 1990s, new MUTCD-compliant signs and high-intensity lighting were installed on the Robert Moses Causeway. Additional safety measures included the construction of a new concrete ("Jersey") barrier and the implementation of sand-filled crash attenuators.

In September 1997, long-term reconstruction began on the original Robert Moses Causeway span, which carries the two southbound lanes over Great South Bay. This project consisted of the replacement of the bridge deck and roadway, renovation of the steel arch span, and the installation of fiberglass jackets over the causeway. During reconstruction of the southbound causeway, the three-lane northbound span carried both northbound and southbound traffic. A moveable concrete barrier allowed for two lanes of traffic in one direction, one lane in the opposing direction, and for easy changeover when appropriate. The $80 million project was completed on June 30, 2000.

This 2018 photo shows the southbound Robert Moses Causeway at EXIT RM2 (NY 27A /  Montauk Highway) in West Islip. (Photo by Steve Anderson.)

ADDING CAPACITY ACROSS FIRE ISLAND INLET? While the opening of the parallel Great South Bay span alleviated some congestion, the Fire Island Inlet crossing continued to serve as a choke point. In its 1975 report Maintaining Mobility, the Tri-State Regional Planning Commission recommended studies on adding a parallel span over Fire Island Inlet:

Increasing recreational activity on Fire Island will place heavy traffic on the two-lane bridge over Fire Island Inlet. Providing additional lanes, instituting traffic controls, introducing shuttle bus service, or implementing a combination of these options should be considered.

The new span, which would serve traffic bound for Robert Moses State Park and Fire Island National Seashore, was designated as a "future needs" project to be completed after 1985. While the parallel Fire Island Inlet Bridge was never completed, a new four-lane span over the inlet may fulfill this traffic need one day.

The NYSDOT has a long-range plan to replace the existing two-lane Fire Island Inlet Bridge, a steel-arch span and causeway between Jones Beach (Oak Beach) Island and Fire Island. In 2004, the state began design studies (for which $2.2 million has been allocated) on replacing the bridge, and in the interim, made repairs that would extend the life of the existing span by at least ten years. Any replacement span likely would have four lanes, and also have capacity for bicycle and pedestrian traffic.

CURRENT AND FUTURE IMPROVEMENTS: With the completion of the southbound Great South Bay span project in 2000, the NYSDOT embarked on a project to rehabilitate the superstructure and repair the pilings on the northbound Great South Bay Bridge. The $69 million project was completed in 2005. The NYSDOT has a long-range plan to build landside bike path connectors along the roadways from EXIT RM2 (NY 27A) south to the Ocean Parkway as part of the proposed Robert Moses Bikeway.

According to the NYSDOT, the Robert Moses Causeway handles approximately 30,000 vehicles per day (AADT) between the Southern State Parkway and Montauk Highway, and approximately 20,000 vehicles per day over Great South Bay.

This 2018 photo shows the southbound Robert Moses Causeway at the Captree Inlet Drawbridge, which connects Captree Island with Jones Beach (Oak Beach) Island. (Photo by Steve Anderson.)

SOURCES: "Restoration and Protection of Fire Island," Long Island State Park Commission (1938); "Captree Parkway and Span Opened," The New York Times (6/13/1954); Arterial Progress 1959-1965, Triborough Bridge and Tunnel Authority (1965); Public Works: A Dangerous Trade by Robert Moses, McGraw-Hill (1970); The Power Broker by Robert A. Caro, Vintage Books-Random House (1974); Maintaining Mobility, Tri-State Regional Planning Commission (1975); History of the Long Island State Parkway System, New York State Department of Transportation (1985); Robert Moses: Single-Minded Genius by Joann P. Krieg, Heart of the Lakes Publishing (1989); "Beach Causeway Closure Delayed" by Sylvia Adcock, Newsday (5/29/1997); "Ask Dr. Conehead" by Kim Nava, Newsday (4/05/1998); "Road Delays Ahead" by John Valenti, Newsday (5/26/2000); "DOT Announces Traffic Projects," Suffolk Life (5/30/2001); New York Metropolitan Transportation Council; Ralph Herman; Larry Lucchetti; Nathan W. Perry; Jim Wade; Russ Weisenbacher.

  • Robert Moses Causeway shield by Ralph Herman.
  • Lightposts by Jeff Saltzman.
  • Bike route sign by Richard C. Moeur.





  • Robert Moses Causeway exit list by Steve Anderson.

Back to The Roads of Metro New York home page.

Site contents © by Eastern Roads. This is not an official site run by a government agency. Recommendations provided on this site are strictly those of the author and contributors, not of any government or corporate entity.