Where else? Houston, Texas of course.
When constructed during the 1960s, the I-10 Katy from Houston, known as the Katy Freeway, was built with six to eight lanes wide barring side lanes, being modest by Houston standards because existing traffic demand to the farming area of West Houston was relatively low. As the population and economic activity increased in the area vehicular traffic increased, reaching an annual average daily traffic (AADT) of 238,000 vehicles just west of the West Loop in 2001.
In 2000 increased traffic levels and congestion led to plans being approved for widening of the freeway to 16 lanes with a capacity for 200,000 cars per day. An old railway running along the north side of the freeway was demolished in 2002 in preparation for construction which began in 2004. The interior two lanes in each direction between SH 6 and west I-610, the Katy Freeway Managed Lanes or Katy Tollway, were built as high-occupancy toll lanes and are managed by the Harris County Toll Road Authority. The section just west of SH 6 to the Fort Bend–Harris county line opened in late June 2006. Two intersections were rebuilt (Beltway 8 and I-610), toll booths were added, together with landscaping as part of Houston’s Highway Beautification Project. Most of the section between Beltway 8 and SH 6 had been laid by September 2006 and work was completed in October 2008.
Tolls on the managed lanes vary by vehicle occupancy, axle count and time of day. High occupancy vehicles may travel for free at certain times.
Interstate 10 (I-10) is the major east–west Interstate Highway in the Southern United States. In the U.S. state of Texas, it runs east from Anthony, at the border with New Mexico, through El Paso, San Antonio and Houston to the border with Louisiana in Orange, Texas. At just under 880 miles (1,420 km), the Texas segment of I-10, maintained by the Texas Department of Transportation, is the longest continuous untolled freeway in North America that is operated by a single authority, a title formerly held by Ontario Highway 401.