The Rock County Sheriff's Office is investigating a fatal traffic accident. 45-year-old Loeun Oeun of Janesville was pronounced dead at the scene of the accident on South Summerville Road near the I-43 overpass in Clinton Township early yesterday afternoon. Oeun was a back-seat passenger in a car driven by 46-year-old Sokhon Pek of Janesivllle. Authorities say Pek appears to have been traveling southbound on the gravel road and lost control. Her vehicle rolled several times in the ditch before coming to rest on its roof. Pek and a front seat passenger were both wearing seatbelts, Oeun was not.