Trooper Isbell and Trooper Robert C. Foltz were investigating a collision on I-40 west of El Reno. Trooper Isbell was measuring skid marks when he was struck by a vehicle driven by a Des Moines, Iowa, woman. The woman had been driving for a long period of time and was very tired and sleepy and had nearly struck the patrol unit before colliding with the Trooper.

She was charged with negligent homicide.