The crash was reported shortly after 8 a.m. near 7th Street, according to the California Highway Patrol.
Details are limited, but Eyewitness News has learned that a driver suffered a medical emergency and later died.
Authorities believe that driver may have also caused the crash.
As many as six cars were involved, investigators said.
It's unclear if anybody else was injured, or how long the transition road was expected to remain closed.