New York State Route 400  New York State Route 400 (NY 400) is a state highway located within Erie County, New York, in the United States. The northwest end is connected to the New York State Thruway (Interstate 90 or I-90) and the southeast end terminates at NY 16 in the town of Aurora. NY 400, a limited-access highway known as the Aurora Expressway, roughly parallels NY 16 between the two locations. It is most commonly used to carry traffic from Buffalo to the village of East Aurora, where Fisher-Price and Moog, Inc are headquartered. It is a busy commuter route to the southern suburbs. NY 400 is signed as a north–south route, although about half of the route runs more east–west. The northwest end of NY 400 is in the southern part of Buffalo at the Thruway. The southeast end is north of the hamlet of South Wales, which is located in the town of Wales. At this end, the route connects to Olean Road and continues south as NY 16. The highway crosses Cazenovia Creek just before ending. NY 400 begins northwest of the hamlet of South Wales in the town of Aurora; however, South Wales, situated less than southeast of the route's end, is located in the adjacent town of Wales. At its southern end, NY 400 splits off of Olean Road, taking with it NY 16 which occupies Olean Road to the south. The two routes head north-northwest from here as the Aurora Expressway through rural areas in the town of Aurora. After passing by Emery County Park, NY 16 leaves the expressway back onto Olean Road on one of three junctions that only allow access in one cardinal direction, this one to the south as a northbound exit and southbound entrance. NY 400 continues heading in a primarily northward direction; however, it briefly turns back in a slight east direction to avoid the village of East Aurora. Remaining rural, NY 400 crosses just to the east of East Aurora, encountering U.S. Route 20A (US 20A) and NY 78 (Big Tree Road) at a northbound entrance and southbound exit. North of here, entering the town of Elma, it turns to the west to meet with Maple Street at the final single-direction junction, a northbound entrance and southbound exit. The expressway then turns northwest to intersect with Jamison Road (formerly NY 422) by way of a full diamond interchange.