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. The "Mixing Bowl" nickname is now more commonly used to refer to the Springfield Interchange, where I-395, I-495, and I-95 converge in nearby Springfield. The Mixing Bowl The Mixing Bowl originally opened in 1942 as the junction of the Shirley Highway with the connection to the Arlington Memorial Bridge and the connection to Lee Boulevard (now Arlington Boulevard). The western half, towards Lee Boulevard, was a full three-level Y interchange. The eastern half, towards the Memorial Bridge, was missing a ramp to enter the Shirley Highway northeastbound. Just south of the west half was another interchange, a single Y connecting to Arlington Ridge Road. From 1970 to 1973, as part of a total reconstruction of the Shirley Highway, the interchange was totally rebuilt to eliminate all weaving of traffic, mainly by the use of collector/distributor roads. The former cloverleaf with Hayes Street became a system of ramps to the various roads. The ramp from I-395 south to Route 27 towards the Memorial Bridge was removed, and a pair of ramps at the crossing of Route 27 and Route 110 made some of the ramps at Route 110 (then known as the Jefferson Davis Highway) redundant. Finally, a two-lane reversible HOV roadway was added in the median, becoming a four-lane two-way road from the eastern part of the interchange into Washington. Special ramps to Route 27 towards the Memorial Bridge and to the Pentagon south parking lot (via Eads Street) were provided for HOV traffic. Roads Shirley Highway (I-395) The Henry G. Shirley Memorial Highway was built to take traffic off the Highway Bridge (now the 14th Street Bridge). The first phase, from the bridge to Arlington Ridge Road, was completed in 1942. This began at an existing cloverleaf interchange with the Mount Vernon Memorial Highway and ran southwest, parallel to the existing Jefferson Davis Highway (U.S. Route 1), to a point southeast of the