The crash was reported on eastbound Highway 80, just east of University Avenue, at about 4:30 a.m. when the bicyclist was struck attempting to cross the lanes to the center divide, Officer James Evans said.
Officers arriving on the scene located the bicyclist down in the roadway and learned that he had been hit by a Ford pickup truck, according to the CHP.
The bicyclist, identified as a resident of Jamaica Plain, Massachusetts, was pronounced dead at the scene.
The driver of the truck, a 41-year-old man from Mariposa County, was unharmed in the collision and cooperated with the CHP investigation.
The CHP is actively investigating the crash and is asking anyone with information about the incident to call (510) 450-3821 or (800) TELL-CHP.
