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Pentagon road network
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 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.
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 Pentagon. That section included an interchange with Boundary Channel Drive, which served the Pentagon's north parking lot, and a bridge over the Rosslyn Connecting Railroad. US 1 was routed onto it, as the existing US 1 was cut in several places by ramps.
After crossing the Jefferson Davis Highway, where US 1 exited to the south, the Shirley Highway turned west, with an interchange to access the south parking lot. (Hayes Street now crosses under the highway there.) Southwest of the Pentagon, the connection to the Arlington Memorial Bridge (now Route 27) merged, and soon after was a split for the connection to Lee Boulevard (now also Route 27, Washington Boulevard). Just past that, the original construction turned southeast to end at Arlington Ridge Road.
The extension beyond to Route 7, also built by the federal government, opened October 23, 1943 and became a divided highway on October 30, 1944. The extension beyond Route 7 to US 1 near Occoquan was built by the Virginia Department of Highways as State Route 350 from 1945 to 1952. (SR 350 was also signed along the Federally built portion southwest of US 1.)
On December 17, 1964, the road system was transferred to Virginia, and soon after the Shirley Highway became part of Interstate 95. With the cancellation of I-95 through Washington, D.C., it was renumbered to I-395 in 1977.
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Pentagon road network
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 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.
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 Pentagon. That section included an interchange with Boundary Channel Drive, which served the Pentagon's north parking lot, and a bridge over the Rosslyn Connecting Railroad. US 1 was routed onto it, as the existing US 1 was cut in several places by ramps.
After crossing the Jefferson Davis Highway, where US 1 exited to the south, the Shirley Highway turned west, with an interchange to access the south parking lot. (Hayes Street now crosses under the highway there.) Southwest of the Pentagon, the connection to the Arlington Memorial Bridge (now Route 27) merged, and soon after was a split for the connection to Lee Boulevard (now also Route 27, Washington Boulevard). Just past that, the original construction turned southeast to end at Arlington Ridge Road.
The extension beyond to Route 7, also built by the federal government, opened October 23, 1943 and became a divided highway on October 30, 1944. The extension beyond Route 7 to US 1 near Occoquan was built by the Virginia Department of Highways as State Route 350 from 1945 to 1952. (SR 350 was also signed along the Federally built portion southwest of US 1.)
On December 17, 1964, the road system was transferred to Virginia, and soon after the Shirley Highway became part of Interstate 95. With the cancellation of I-95 through Washington, D.C., it was renumbered to I-395 in 1977.