High Five Interchange

The High Five Interchange in Dallas, Texas, is a monumental highway interchange located where Interstate 635 meets US Highway 75. One of the city's first five-level stack interchanges, it replaced an outdated 1960s cloverleaf interchange that was notorious for massive traffic jams and limited local access. The name comes from the high-five gesture and refers to the five elevated ramps that handle the left-turn movements. Standing about 118 feet (36 meters) tall, equivalent to a twelve-story building, and incorporating 43 bridges, the structure is an impressive example of modern transportation infrastructure. The uppermost ramps rise as high as 98 feet (30 meters) into the air, while the lowest level of US 75 runs about 20 feet (6 meters) below street level.

The design carries various traffic flows across five levels, including regular lanes, separated high-occupancy-vehicle lane systems for Interstate 635, and direct connector ramps that eliminate the formerly problematic left turns. One special feature for visitors and users is the Cottonwood Trail, a hiking and biking trail that passes beneath all levels of the interchange, offering a green oasis in the middle of a concrete landscape. The precast concrete components are also decorated with engravings and special color treatments mandated by the Texas Department of Transportation to enhance the interchange's appearance.

The project, which began in 2002 and was completed in December 2005, was an engineering challenge solved with innovative methods such as the use of precast concrete segments and specialized machinery from Italy. Construction was planned so that existing traffic could largely be maintained throughout the building phase. Thanks to its enormous size, innovative design, and rapid completion, the High Five Interchange was named "Public Works Project of the Year" by the American Public Works Association in 2006. The trade magazine Popular Mechanics also counts the interchange among the world's most unusual roads and calls it a five-level marvel of engineering.