The Missouri Dept. of Transportation is building its second “diverging diamond” interchange design that requires motorists at an interchange to temporarily drive on the left side of the road. It was devised by an engineer in graduate school who wasn’t aware the concept already existed in Europe. The Federal Highway Administration has tested and presented the design, and a dozen states are considering using it Photo: MODOT Springfield, Mo., diverging diamond design moves left-turning traffic more easily. The design calls for the approach road on either side of the interchange to curve to the left, so the driver can easily
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.