SAGTIKOS PARKWAY
PARKWAY HISTORY
The Sagtikos Parkway is a major north–south route in Su olk County, originally constructed in the 1950s as part of Robert Moses’ vision for improved parkway connectivity across the region.
It was designed to link the Northern State Parkway and the Southern State Parkway, e ectively serving as a central spine connecting eastern and western Long Island.
The parkway was named after the nearby Sagtikos Manor, a historic estate dating back to the 17th century.
Over the decades, the Sagtikos has evolved into a heavily tra cked commuter route due to Long Island’s population growth and suburban expansion.
Despite its scenic, limited-access design, it now faces congestion and aging infrastructure issues. Various improvement projects have been proposed, including capacity expansions and interchange upgrades, to address increasing tra c demands.
DRONE IMAGES
SHOWING THE EXIT 41A ON-RAMP TO SAGITKOS NORTHBOUND.
CONSTRUCTION VEHICLES STAGED ALONG THE LEFT SIDE OF EXIT RAMP, WITH CONES AND LIGHTING TO THE RIGHT OF THE SHOULDER.
TRUCKS NOT PERMITTED
Sagtikos Parkway Calculations
Number of lanes: 2 lanes
Lanes width: 11 ft
Shoulder width: 6 inches
Location: Suburban / Urban Interchange
CALCULATION
The calculations presented for the Sagtikos Parkway provide a clear application of the Highway Capacity Manual (HCM) methodology for basic freeway segments in a suburban/urban context.
Using a base free- ow speed (BFFS) of 70 mph, appropriate adjustments were applied for lane width (−1.9 mph), lateral clearance (−3.0 mph), number of lanes (−4.5 mph), and interchange density (−1.3 mph), resulting in an adjusted free- ow speed (FFS) of 59.3 mph. The computed passenger car ow rate per lane—2,450 pc/hr/ln—accounts for the peak hour factor (PHF = 0.92), number of lanes (2), and the heavy vehicle adjustment factor (which is 1.0 due to 0% truck percentage).
Dividing ow rate by FFS yields a density of 41.3 pc/mi/ln. According to HCM thresholds, this corresponds to Level of Service (LOS) E, which is consistent with high tra c volumes and limited maneuverability. The methodology is correct, and all relevant factors appear to be reasonably considered.
/ MARTILOTTA / WASIUTA
GARCIA
REFERENCES
Wikipedia contributors. (n.d.). Sagtikos State Parkway. Wikipedia. Retrieved May 4, 2025, from https://en.wikipedia.org/wiki/Sagtikos_State_Parkway
New York City Roads. (n.d.). Sagtikos State Parkway. Retrieved May 4, 2025, from http://www.nycroads.com/roads/sagtikos/
New York State Roads. (n.d.). Southern State & Sagtikos Parkway. Retrieved May 4, 2025, from https://nysroads.com/list-smsp.php
New York State Department of Transportation. (2024, July 8). Traveler advisory: Sagtikos Parkway construction update. Retrieved May 4, 2025, from https://www.dot.ny.gov/news/traveler-advisories/2024/2024-07-082
