9 million bicycles, but what about the cars in Beijing?

Forget there being "9 million bicycles in Beijing," that's not a fact. Indeed, motor vehicle traffic is fast becoming a big problem that has led to unsustainable pollution and draconian rules in some parts of the city. Now, Nan Ji of the Hebei United University in China and colleagues have developed an algorithm to help traffic planners optimize the flow of traffic across roundabouts. Read more