IH 37 was added to the original Interstate system in October 1957. It was included within the Texas Interstate Highway System by the State Highway Commission in 1962 with 142 miles.3
The proposed section of IH 37 north of Downtown San Antonio to IH 410 was the North Expressway, a route connecting Downtown with the airport. Original plans called for the freeway to travel a straight line north from Downtown. However, local opposition arose due to the potential local impacts of the freeway. A lawsuit by the San Antonio Conservation Society resulted in an injunction preventing construction of the freeway as an Interstate in 1967.
Opposition to the freeway project remained through the late 1960s and early 1970s. The struggle reached a national audience when the freeway was profiled in Helen Leavitt’s book Superhighway-Superhoax. With its proximity to or passage through parkland, a college campus, schools, residential neighborhoods and other sensitive areas, the route was changed to avoid these features. This resulted into the number of S-curves along the freeway between IH 35 and IH 410. In 1973, the freeway was resurrected as a project to be built without federal funds as a new alignment for U.S. 281. Construction ensued through the mid-1970s, and the Walter McAllister Expressway (U.S. 281) opened to traffic on February 7, 1978.4 The systems interchange providing direct connection ramps between U.S. 281 and IH 410 did not begin construction until 2006. It was completed in June 2008.