Earlier reports indicated that it would be closed in both directions for the next day or two.
The CHP said the boulder was first reported around 3:05 a.m. on the roadway just east of Palomares Road, and caused at least one traffic collision. There are no immediate reports of injuries in the crash. It was cleared around 6:15 a.m.
ACE was holding trains in Livermore due to the incident.
Check drive times and traffic maps.