Passersby discovered the Cupertino resident unconscious on the right shoulder of Highway 9, south of Redwood Gulch Road, around 3:50 p.m.
Lipson was pronounced dead at the scene at about 4:15 p.m. The cause of his death has not yet been determined.
Investigators believe Lipson may have lost control of his bicycle and struck a tree, according to the California Highway Patrol.
The northbound lane of Highway 9 south of Redwood Gulch Road was closed for about an hour and a half while the investigation was carried out