The fastest speed achieved on a bicycle was 204.73 kph (127.243 mph), by Jose Meiffret (France), July 16, 1962, on the German Autobahn from Freiburg, behind a car"
from "Cycling." Encyclopedia Britannica. Volume V. Chicago: Encyclopedia Britannica, 1984
John Howard might have something to say about that......although doing it behind a car on the highway is just as impressive...
http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm