Left turns are the bane of traffic engineers and drivers on busy streets. Gilbert Chlewicki has brainstormed a solution that is more efficient, less costly, and less time-consuming for drivers than previous street designs (like dedicated left-turn lanes, multi-leveled roadways, large-scale traffic roundabouts, or grade separation). It is the diverging diamond interchange, and it is elegant in its simplicity when compared to existing freeway interchanges or intersections of major traffic arteries. The article describes the operational advantages, and here is an animated visualization showing a DDI in action.
DDIs and other design innovations do not, of course, relieve us of the responsiblity for developing swift and efficient mass transit (high speed rail, urban buses and trams) like the systems already in place in Europe and Japan, or for developing a viable alternative to the harshly-polluting internal combustion engine, or for revising the hub and spoke system of air travel. But every little bit helps.