324 runs in a more southeasterly direction, serving as the main commercial strip on Grand Island, before it overlaps I-190 in order to cross the Niagara River. Once on the mainland, the structure of exits on I-190 allows only the westbound portion of NY 325 to use Grand Island Boulevard west of I-190's exit 15, following Grand Island Boulevard past the exit to an intersection with NY 266, then turning right to follow it to exit 17 to merge with I-190. The eastbound route of NY 324 is unable to do so; instead, it parts company with the Interstate Highway on the other side of the river at exit 15, where it turns north to parallel I-190 on Kenmore Avenue. The eastbound portion of Grand Island Boulevard on this stretch is maintained as reference route 950C. After , it veers east onto Tonawanda's portion of Grand Island Boulevard for to a junction with Sheridan Drive. The latter carries NY 325, a route that begins at NY 266 on the banks of the Niagara and passes through a commercial and industrial area of the town of Tonawanda. NY 324 takes on the Sheridan Drive name here and assumes a more due easterly course across northern Erie County. Though the street is signed as a state highway on both NY 324 and NY 325, most residents simply refer to this road by its local name. Through much of this portion, the road is divided, with a tree-lined median strip. Businesses, both local and national, line both sides of the road and traffic is heavy. It crosses some other major strips such as Niagara Falls Boulevard (U.S. Route 62 or US 62), a major contributor to traffic on Sheridan due to the proximity of the Boulevard Mall, and Millersport Highway (NY 263), which feeds the Amherst campus of the University at Buffalo. In Amherst it meets the Youngmann Expressway (I-290) where NY 240 (Harlem Road), reaches its northern end. Past the Youngmann development abates, green returns to the roadside and the median ends, although the road remains four-lane and high-volume. There is another pocket of development around the Wegmans supermarket north of Williamsville, which has seen some rapid growth in the last few years. NY 324 crosses its last major route, Transit Road (NY 78), on an overpass just north of the once-thriving Eastern Hills Mall, which had been the premier mall in