A small mystery from Robocar history was resolved recently, and revealed at the DARPA grand challenge reunion at CMU. The story is detailed here at IEEE spectrum and I won't repeat it all, but a brief summary goes like this. In the 2nd grand challenge, CMU's Highlander was a favourite and doing very well. Mid-race it started losing engine power and it stalled for long enough that Stanford's Stanley beat it by 11 minutes. It was discovered recently a small computerized fuel injector controller in the Hummer (one of only two) may have been damaged in a roll-over that Highlander had, and if you pressed on it, the engine would reduce power or fail.