Major Highway Systems of Houston
The eight-county Greater Houston metropolitan area contains over 25,000 miles (40,000 km) of the roadway, of which 10%, or approximately 2,500 miles (4,000 km), is a limited-access highway. The Houston region’s extensive freeway system handles over 40% of the regional daily vehicle miles traveled (VMT). Arterial roads handle an additional 40% of daily VMT, while toll roads, of which Greater Houston has 180 miles (290 km), handle nearly 10%.
Greater Houston possesses a hub-and-spoke limited-access highway system, in which a number of freeways radiate outward from Downtown, with ring roads providing connections between these radial highways at intermediate distances from the city center. The city is crossed by three Interstate highways, Interstate 10, Interstate 45, and Interstate 69 (commonly known as U.S. Route 59), as well as a number of other United States routes and state highways. Major freeways in Greater Houston are often referred to by either the cardinal direction or geographic location they travel towards. Highways that follow the cardinal convention include U.S. Route 290 (Northwest Freeway), Interstate 45 north of Downtown (North Freeway), Interstate 10 east of Downtown (East Freeway), Texas State Highway 288 (South Freeway), and Interstate 69 south of Downtown (Southwest Freeway). Highways that follow the location convention include Interstate 10 west of Downtown (Katy Freeway), Interstate 69 north of Downtown (Eastex Freeway), Interstate 45 south of Downtown (Gulf Freeway), and Texas State Highway 225 (La Porte or Pasadena Freeway).
Three loop freeways provide north-south and east-west connectivity between Greater Houston’s radial highways. The innermost loop is Interstate 610, commonly known as the Inner Loop, which encircles Downtown, the Texas Medical Center, Greenway Plaza, the cities of West University Place and Southside Place, and many core neighborhoods. The 88-mile (142 km) State Highway Beltway 8, often referred to as the Beltway, forms the middle loop at a radius of roughly 10 miles (16 km). A third, 180-mile (290 km) loop with a radius of approximately 25 miles (40 km), State Highway 99 (the Grand Parkway), is currently under construction, with six of eleven segments completed as of 2018. Completed segments D through G provide a continuous 70.4-mile (113.3 km) limited-access tollway connection between Sugar Land, Katy, Cypress, Spring, and Porter.
A system of toll roads, operated by the Harris County Toll Road Authority (HCTRA) and Fort Bend County Toll Road Authority (FBCTRA), provides additional options for regional commuters. The Sam Houston Tollway, which encompasses the main lanes of Beltway 8 (as opposed to the frontage roads, which are untolled), is the longest tollway in the system, covering the entirety of the Beltway with the exception of a free section between Interstate 45 and Interstate 69 near George Bush Intercontinental Airport. The region is serviced by four spoke tollways: a set of managed lanes on the Katy Freeway; the Hardy Toll Road, which parallels Interstate 45 north of Downtown up to Spring; the Westpark Tollway, which services Houston’s western suburbs out to Fulshear; and Fort Bend Parkway, which connects to Sienna Plantation. Westpark Tollway and Fort Bend Parkway are operated conjunctly with the Fort Bend County Toll Road Authority.
Greater Houston’s freeway system is monitored by Houston TranStar, a partnership of four government agencies which is responsible for providing transportation and emergency management services to the region.
Greater Houston’s arterial road network is established at the municipal level, with the City of Houston exercising planning control over both its incorporated area and extraterritorial jurisdiction (ETJ). Therefore, Houston exercises transportation planning authority over a 2,000-square-mile (5,200 km2) area over five counties, many times larger than its corporate area. The Major Thoroughfare and Freeway Plan, updated annually, establishes the city’s street hierarchy, identifies roadways in need of widening, and proposes new roadways in unserved areas. Arterial roads are organized into four categories, in decreasing order of intensity: major thoroughfares, transit corridor streets, collector streets, and local streets. Roadway classification affects anticipated traffic volumes, roadway design, and right of way breadth. Ultimately, the system is designed to ferry traffic from neighborhood streets to major thoroughfares, which connect into the limited-access highway system. Notable arterial roads in the region include Westheimer Road, Memorial Drive, Texas State Highway 6, Farm to Market Road 1960, Bellaire Boulevard, and Telephone Road.