The man has been identified as Andrew Magana of Fresno.
Investigators first responded to a stopped car on the transition ramp from Highway 99 and Highway 180 just after midnight.
Witnesses reported that the driver of that car was running in the area.
The car was located with the engine running and officers moved it out of the road, but the driver was not found.
Shortly after, the CHP received several reports of a person running in and out of traffic on 99 near Fresno Street.
The man, who we now know is Magana, was hit by a car just south of Belmont Avenue, where he died.
The 22-year-old man who was driving the car was also injured and taken to the hospital.
Investigators say the 22-year-old was under the influence of alcohol and arrested for DUI.