The five-vehicle collision occurred shortly after 7 a.m. on Highway 152 just west of Lake Road.
A 25-year-old Los Banos man driving a 2021 Tesla was heading west on the highway when he tried to use the eastbound lane to pass a Peterbilt big-rig but struck a 2018 Honda that was driving east, CHP Officer Alfredo Uribe said in a news release.
The collision caused the Tesla to then hit a 2017 Dodge head-on, causing the Dodge to also collide with the big rig, according to Uribe. The Tesla spun out of control and hit a 2020 Subaru.
A 7-year-old girl in the Dodge was pronounced dead at the scene while a 4-year-old girl was taken to Santa Clara Valley Medical Center, where she succumbed to her injuries.
A 1-year-old boy in the Dodge was also taken to the hospital, as was the Tesla driver, who suffered major injuries, Uribe said.
The CHP is still investigating whether impairment was a factor in the collision.
Anyone with information about the case is asked to call Officer Vasquez from the CHP's Hollister-Gilroy office at (408) 427-0700.