grid pattern, though this pattern is less common in the surrounding areas. Major roads branch out from the downtown district like spokes on a wheel to the highways surrounding the city. The city is belted by three freeways: I-94, which runs along the southern and western portion of the city; U.S. Highway 23 (US 23), which primarily runs along the eastern edge of Ann Arbor; and M-14, which runs along the northern edge of the city. Other nearby highways include US 12 (Michigan Ave.), M-17 (Washtenaw Ave.), and M-153 (Ford Rd.). Several of the major surface arteries lead to the I-94/M-14 interchange in the west, US 23 in the east, and the city's southern areas. The city also has a system of bike routes and paths and includes the nearly complete Washtenaw County Border-to-Border Trail. Bus service The Ann Arbor Area Transportation Authority (AAATA), which brands itself as "TheRide", operates public bus services throughout the city and nearby Ypsilanti. The AATA operates Blake Transit Center on Fourth Ave. in downtown Ann Arbor, and the Ypsilanti Transit Center. A separate zero-fare bus service operates within and between the University of Michigan campuses. Since April 2012, route 98 (the "AirRide") connects to Detroit Metro Airport a dozen times a day. There are also limited-stop bus services between Ann Arbor and Chelsea as well as Canton. These two routes, 91 and 92 respectively, are known as the "ExpressRide". Greyhound Lines provides intercity bus service. The Michigan Flyer, a service operated by Indian Trails, cooperates with AAATA for their AirRide and additionally offers bus service to East Lansing. Megabus has direct service to Chicago, Illinois, while a bus service is provided by Amtrak for rail passengers making connections to services in East Lansing and Toledo, Ohio. Airports Ann Arbor Municipal Airport is a small, city-run general aviation airport located south of I-94. Detroit Metropolitan Airport, the area's large international airport, is about east of the city, in Romulus. Willow Run Airport east of the city near Ypsilanti serves freight, corporate, and general aviation clients. Railroads The city was a major rail hub, notably for freight traffic between Toledo and ports north of Chicago, Illinois, from 1878 to 1982; however, the Ann Arbor Railroad also provided passenger service from 1878 to 1950, going northwest to Frankfort and Elberta on Lake Michigan and southeast to Toledo. (In Elberta connections to ferries across the Lake could be