DARPA’s Cheetah robot—already the fastest legged robot in history—just broke its own land speed record of 18 miles per hour (mph). In the process, Cheetah also surpassed another very fast mover: Usain Bolt. According to the International Association of Athletics Federations, Bolt set the world speed record for a human in 2009 when he reached a peak speed of 27.78 mph for a 20-meter split during the 100-meter sprint. Cheetah was recently clocked at 28.3 mph for a 20-meter split. The Cheetah had a slight advantage over Bolt as it ran on a treadmill, the equivalent of a 28.3 mph tail wind, but most of the power Cheetah used was to swing its legs fast enough, not to propel itself forward.

I have to point out that Usain Bolt does not have a tether attached to him to protect himself from falls if he tries to run too fast, which is another advantage for the robot.