Police say shell casings were found at four locations around the stadium.
They blocked off Millbrook between Barstow and Bulldog, and Bulldog between Millbrook and Cedar, for their investigation.
Witnesses said the suspect was shooting from a moving car while thousands of Fresno State fans were inside the stadium.
Investigators do not believe there was a specific target, and there were no injuries.
Both Millbrook and Bulldog were closed Saturday evening, but police said they planned to have the roads reopened before the end of the game.