A man witnessed his friend crash his motorcycle and suffer serious injuries near Mission Valley early Thursday.
California Highway Patrol officers said the motorcyclist was found just off the road near where the onramp from Interstate 8 merges with traffic near Texas Street.
A friend who was traveling behind the motorcyclist was the first person to arrive and called for help.
Paramedics treated him briefly on scene before loading him on a stretcher and rushing him off to Scripps Mercy Hospital in an ambulance.
The CHP said it's believed that speed, not alcohol or drugs, was a factor in the crash.
Officers thinking he simply took the onramp too fast and couldn't handle the turn, lost control and wiped out.
