Near the end of the application process, an I.O.C. evaluation committee was permitted to visit London. Bid-committee officials knew that London’s transportation system was a weak spot on the city’s application. “Our nightmare was it would take forever to get to the venues,” Mills recalled. A bid-committee team planned the routes that I.O.C. members would travel around the city, and G.P.S. transmitters were planted in all of the I.O.C. members’ vehicles so they could be tracked. From the London Traffic Control Center, near Victoria Station, where hundreds of monitors display live feeds from London’s comprehensive CCTV surveillance system, each vehicle was followed, from camera to camera, “and when they came up to traffic lights,” Mills said, “we turned them green.”