CHP officers responded to westbound Highway 24 near the 51st Street on-ramp, just east of Interstate Highway 580, at about 4:45 a.m., the CHP said.
At least one person was killed in a crash, the CHP said. Further details about the crash were not immediately available.
A Sig-alert was issued at 5:16 a.m. when the CHP blocked all westbound Highway 24 lanes. It was cancelled at 6:15 a.m.