Roberto Guerrero, who came back from serious...

Roberto Guerrero, who came back from serious head injuries suffered in a crash last fall, was knocked unconscious for a brief period in an accident during practice for today’s Miller 200 at Milwaukee.

Guerrero, 29, was conscious, alert and talking while being removed from his wrecked Lola.

Dr. Terry Trammell, the director of the Horton Safety Team, which handles medical emergencies at Indy-car races, said the Colombian driver was taken by ambulance to Milwaukee County General Hospital, where he was to kept overnight for observation.