Like a tracer running through the veins of the city, networks of air quality sensors attached to bikes can help measure an individual's exposure to pollution and draw a dynamic map of the urban air on a human scale, as in the case of the Copenhagen Wheel developed by new startup Superpedestrian.
The first autonomous cars date back to the late 20th century. But recent increases in sophistication and reductions in cost - reflected, for example, in cheap LIDAR systems, which can 'see' a street in 3D in a way similar to that of the human eye - are now bringing autonomous cars closer to the market.
Some trash is recycled, some is thrown away, some ends up where it shouldn't end up.
Cities are 2% of the earth's crust, but they are 50% of the world's population.
As people talk, text and browse, telecommunication networks are capturing urban flows in real time and crystallizing them as Google's traffic congestion maps.