Penns Neck Circle is a traffic circle in the Penns Neck section of West Windsor Township, New Jersey, United States. It is located at the junction of US 1 and Washington Road (CR 571 and signed but unofficial CR 526). It is a major intersection, as Washington Road is one of three connections between US 1 and Princeton, New Jersey.
While technically a traffic circle, the Penn's Neck Circle has been modified to closely resemble a traditional intersection. It is signal-controlled, and US 1 passes through the circle at grade level, making the circle essentially a set of four turning lanes around a straight-only intersection. This arrangement is unsatisfactory, resulting in traffic backups on both Washington Road and US 1. At peak hours, a vehicle attempting continue through the intersection along Washington Road or to make any left turn must wait through several light cycles to complete the maneuver.
Exacerbating this congestion are the business parcels located at the intersection. Until recently, all four quadrants were occupied by gas stations, adding frequently-used exit and entrance ramps to the mix of multi-directional traffic. The gas station in the southwest quadrant has been demolished, its footprint being filled in with green space; the one in the northeast quadrant is now occupied by an AT&T telephone store. The gas station in the southeast quadrant is the only one still in regular use, as the gas station in the northwest quadrant has been permanently closed.