the new shirley highway included the "mixing bowl" interchange complex near the newly completed pentagon (war department building), which was completed in 1944. at this location, the state route 27 freeway (washington blvd.) merges with the shirley highway and then branches off again. the original interchange had a merge section each way, about 1/3 mile long, with a third "mixing lane" where the vehicles would weave when they wanted to change to the other freeway. it was rebuilt in the 1960s. after rebuilding, it was the largest interchange complex in the world. there are currently 52 lane-miles of roadways and ramps, with four freeway junctions and numerous local ramps, and with several interchanges to the reversible express (hov) roadway, all within a section of the shirley highway.