One month (October 2009) of traffic information (1534 vehicles) is condensed in a 24h day. The path's colors represent average traffic speeds (greenish and cooler for higher traffic speeds, reddish and hotter for sluggish traffic). Areas with predominantly slow traffic are also colored.
Lisbon, Portugal. More info in: pmcruz.com/information-visualization/traffic-in-lisbon-condensed-in-one-day