A Richmond resident was involved in a crash early Saturday morning in Lafayette County.  The accident occurred shortly after midnight on I-70, about one mile east of the Oak Grove exit.  The Highway Patrol reports Rodney Walker, 46, was eastbound on the interstate when he traveled off the roadway, struck an embankment, and came to rest in a creek.  He was taken to Centerpoint Hospital with moderate injuries.  His passenger, Jayla McDonald, 35, of Grain Valley, was not injured.  Walker was cited for driving while intoxicated, no seat belt, and failing to drive within a single lane resulting in an accident.