The city of Hangzhou runs the largest bikeshare program in the world. Photo by David Tubau.

Carnegie Mellon University industrial design students Jonathan Ota and Ethan Frier developed the Aura system that brings attention to bicyclists by lighting up their bike. The students incorporated six groups of three tri-colored LEDs attached to the rims of a bike. The lights are powered by a generator built into the front hub.

A version of this post was originally published in Portuguese by Maria Fernanda Cavalcanti on TheCityFix Brasil on December 12, 2011. 

Katy Beveridge, a student of media, illustration and graphic design, created short animations using bicycle wheels. Part of her final year dissertation, Beveridge created the project as an attempt to understand how animation gets created.

Ron Arad's tempered steel wheels give a surprisingly smooth ride the faster you go. Photo via Ron Arad.

Chapter L by Paul Barter in UNEP's newest report presents three-wheeled passenger cars as a significant and acceptable component of the urban transport system in developing countries. Photo by Brett Davies.