The Pentagon road network is a system of highways, mostly freeways, built by the United States federal government in the early 1940s to serve the Pentagon in northern Virginia. The roads, transferred to the Commonwealth of Virginia in 1964, are now largely state highways. The main part of the network is the Mixing Bowl at Interstate 395 (Shirley Highway) and Route 27 (Washington Boulevard), named because it had major weaving issues with traffic "mixing" between the two roads before it was rebuilt in the early 1970s.