The Collaborative International Dictionary of English v.0.48:

roadkill \road"kill\, n. sing. & pl.
   The body of an animal killed by a vehicle on a road; as, it
   is illegal in most places for a restaurant to serve roadkill
   as food for people. Also used metaphorically; as, "roadkill
   on the information superhighway" (a person or corporation
   defeated by others more expert at using the internet).
   [PJC]

WordNet (r) 3.0 (2006):

roadkill
    n 1: the dead body of an animal that has been killed on a road
         by a vehicle; "vultures usually feed on carrion or
         roadkill"