The Houston highway system consists of 739.3 miles (1189.8 km) of roads, including contains motorways and express roads in ten counties of the metropolitan area. The system uses the structure highway hub-and-spoke (or radial), consisting of several loops. The innermost loop is Interstate 610, which surrounds the center, the Texas Medical Center and several neighborhoods within a range of 16 km in diameter. The Beltway 8 and the central highway, the Sam Houston Tollway, form the central loop with a diameter of about 40 km. He proposed a new highway project, State Highway 99 (Grand Parkway), would form a third loop outside of Houston. Currently, only two of the eleven segments of SR 99 have been completed. Sam Houston Tollway, Houston bypass. Houston also will be found along the route of the future Interstate 69, the NAFTA will link Canada, the United States, the industrial Midwest, Texas and Mexico.Other motorways are planned or under construction Fort Bend Parkway, Hardy Toll Road, Crosby Freeway, and the future Alvin Freeway. Highways throughout the cluster is monitored by Houston TranStar, a partnership of four government agencies that are responsible for providing transportation management and emergency services to the region. Houston TranStar was the first center in the nation that combined transportation and emergency management centers, and the first to bring together four agencies (Texas Department of Transportation, Harris County, Metropolitan Transit Authority of Harris County and the City of Houston) to share their resources. The Metropolitan Transit Authority of Harris County, Houston, Texas, or METRO, provides public transport as buses, light rail and light trucks. The various forms of public transport METRO yet connected all the big city suburbs. A METRORail on Main Street in downtown Houston.The train service METRO light rail began on 1 January 2004 with the inauguration of the “red line”, covering about 13 km, starting at the stop University of Houston-Downtown (UHD), which passes through the Texas Medical Center and ends at Reliant Park. METRO is currently in design phase of an expansion plan of 10 years, which added five more lines to the existing network. Amtrak, the national passenger rail system, provides service to Houston via the Sunset Limited (Los Angeles-New Orleans), which stops at a train station on the north side of town. The station saw 14,891 movements in fiscal 2008. Mickey Leland Terminal D George Bush Intercontinental Airport.The Texas city has two commercial airports, serving 52 million passengers in 2007. The most important is the George Bush Intercontinental Airport (IAH), the eighth most active of the United States and the sixteenth most active around the world. In 2006, the Department of Transportation and the United States appointed as Bush Intercontinental Airport the fastest growing of the top ten airports in the country. Houston is the headquarters of Continental Airlines and Bush Intercontinental is the largest hub for Continental Airlines. The airline offers more than 700 daily departures from Houston. In early 2007, Bush Intercontinental was called “port of entry” for international travelers by U.S. Customs and Border Protection United States. The Center Air Traffic Control in Houston (Houston Air Route Traffic Control Center, ZHU) is at this airport. The second largest commercial airport is the Airport Houston William P.Hobby (known as Houston International Airport until 1967). The airport operates primarily in small and medium flights and is the only airport in Houston served to Southwest Airlines and JetBlue Airways. The aviation history of Houston’s collection in 1940 Air Terminal Museum located in the old terminal building on the west side of Hobby Airport. The airport has been recognized with two awards for being one of the top five airports in the world and their customer service, awarded by the Airports Council International. The third airport is the city of Houston Ellington Airport (a former basis of the U.S. Air Force) that is used by military, government, NASA and general aviation sectors. The Federal Aviation Administration and the state of Texas selected the “Houston Airport System as Airport of the Year “In 2005, due in large part by its program of 3,100 million dollars to improve the two main airports in Houston.