Interstate 390 (I-390) is a north–south auxiliary Interstate Highway located entirely within New York in the United States. The southern terminus of the route is at the Southern Tier Expressway (I-86 and New York State Route 17 [NY 17]) in the town of Avoca. Its northern terminus is at I-490 (Western Expressway) in Gates, just west of Rochester. North of I-490, the expressway continues as NY 390 to the Lake Ontario State Parkway in Greece. I-390 connects to its parent, I-90 (New York State Thruway), in Henrietta, a southern suburb of Rochester. The route is known as the Genesee Expressway from Avoca to I-590 in Brighton, where it becomes part of the Rochester Outer Loop. In addition to serving Rochester, I-390 serves as an important connecting route between the Rochester metropolitan area and Corning and the rest of the Southern Tier of New York. The freeway also serves several smaller communities between Corning and Rochester, including the Livingston County villages of Dansville and Geneseo. I-390 effectively replaced US Route 15 (US 15) and parallels NY 15, US 15's de facto successor, north of Corning. From Lakeville north to Brighton, the two routes cross paths four times and are located no more than apart along the entire stretch. The first section of the Genesee Expressway opened in the late 1960s, extending from Wayland in the east to Dansville in the west. The entirety of the then-proposed highway was designated as New York State Route 401 (NY 401) in 1970 but redesignated as I-390 . More sections of the freeway opened throughout the 1970s, and I-390 was extended northwestward to cover the southwestern quadrant of the Rochester Outer Loop in 1980 following the elimination of NY 47. I-390 was completed in the early 1980s. Route description In its southern sections, which account for most of the highway's mileage, I-390 is a lightly trafficked freeway of two lanes in either direction going through minimally populated rural areas. Closer to Rochester, it becomes wider to accommodate the increased traffic it handles in the city itself. Steuben and Livingston counties I-390 begins as westbound traffic on the concurrent routes of I-86 and NY 17 proceeds below the overpass carrying those two routes to the west, at an interchange just east of the village of Avoca in Steuben County. The expressway heads northwest through the narrow valley of the Cohocton River to Cohocton, where the river