Oklahoma City is near the geographic center of the United States and is an integral point on the U.S. Interstate Network. The city is served by numerous roads and highways, toll roads, three major airports, a train station, a bus station, and a transit system. Roads and highways Oklahoma City is served by an extensive freeway network. The city's network serves every major city in the region and are 6–8 lanes. Most have a level of congestion significantly lower than most comparably sized cities. In fact, OKC's freeways are rarely congested with the "stop and go" commuter patterns of other major cities. It is often said that one can get from any part of the OKC Metro area to downtown in 30 minutes or less by freeway. The city streets are on a N–S–E–W grid network with major streets one mile separated. The former section of I-40 directly adjacent to downtown was known as the "Crosstown Expressway". The I-40 Crosstown Construction Project relocated the original elevated stretch of highway several blocks to the south. It opened to the public in 2012. Interstate highways Three major interstate routes serve the city in addition to two secondary interstates. Oklahoma City is the only city in the nation dissected by two interstate highways that reach the entire length of the nation (Interstate 40 E-W and Interstate 35 N-S). Interstate 35 Major cities connected: (N) Wichita, Kansas City, Minneapolis. (S) Dallas-Fort Worth, Austin, San Antonio. Interstate 40 Major cities connected: (W) Amarillo, Albuquerque, Los Angeles/Riverside area (terminus). (E) Little Rock, Memphis, Nashville. Interstate 44 Major cities connected: (E) Tulsa, Saint Louis (terminus). (W) Lawton, Wichita Falls, Texas (terminus) Interstate 235 Downtown Oklahoma City I-35/I-40 junction to the I-44/Broadway Extension junction in North Oklahoma City Interstate 240 SW Oklahoma City I-44 to I-40 in East Oklahoma County. Other major thoroughfares Broadway Extension (US-77) North Oklahoma City Lake Hefner Parkway (SH-74) Northwest Oklahoma City Kilpatrick Turnpike (Outer Loop Tollway) North and West Oklahoma City Airport Road (SH-152) – Southwest Oklahoma City Northwest Expressway (SH-3) Northwest Oklahoma City 39th Expressway (SH-66) West Oklahoma City Northeast 23rd Street (US-62) East Oklahoma County Shields Boulevard (US-77) South Oklahoma City Reno Avenue – West/East Central Oklahoma City Air Oklahoma City is a major air transportation and maintenance center, with three major airports and numerous other smaller ones. Will Rogers World Airport (OKC) is the principal commercial airport of the state