Woman, 71, Killed When Semi-Truck Crosses Into Oncoming Lane on Palmdale Road in Adelanto

A 71-year-old woman was killed Tuesday morning when a semi-truck crossed into oncoming traffic on Palmdale Road (State Route 18) in Adelanto, according to the San Bernardino County Sheriff’s Department. Deputies were called to the two-vehicle crash east of Richardson Street at about 7:37 a.m. on Tuesday, Aug. 18, 2026. Investigators said the semi-truck was traveling eastbound when its driver lost control and crossed into the westbound lane, colliding with a dark blue 2022 Chevrolet Silverado.

Updated August 21, 2026: The woman killed has been identified as Dianne Thomas, 71, of Adelanto, according to Victor Valley News, which reported that the San Bernardino County Coroner’s Office released her name. Victor Valley News reported that the semi-truck driver lost control and swerved into the westbound lane, striking Thomas’s Silverado, and that the Sheriff’s Major Accident Investigation Team is still seeking witnesses. No arrest or charge has been reported.

As reported by Victor Valley News, the woman driving the Silverado was pronounced dead at the scene and her name has not been released pending notification of family. The 60-year-old driver of the semi-truck — described by Victor Valley News as a rig operated by BHC Trucking LLC — was taken to a hospital in stable condition. Palmdale Road was shut down in both directions between Richardson Road and Aster Road for several hours while the Sheriff’s Major Accident Investigation Team documented the scene. No arrest, citation or charge has been reported, and the cause remains under investigation. Anyone who witnessed the crash is asked to call the Victor Valley Sheriff’s Station at 760-552-6800, or Sheriff’s Dispatch at 760-956-5001.