The shooting happened at about 3:30 p.m. near San Pablo Avenue and all eastbound lanes have been closed since about 3:45 p.m., according to CHP spokesman Officer Sean Wilkenfeld.
At least one person was airlifted to the hospital and another was taken to the hospital in an ambulance, both with serious injuries, Wilkenfeld said.
Witnesses described the vehicle that appeared to be involved in the shooting as a silver Dodge Charger, and Richmond officers detained the possible suspects a little after 4 p.m. in the city's Iron Triangle neighborhood, according to Richmond police spokesman Lt. Felix Tan.
The shooting appears to be a "targeted" attack, and not random, according to Wilkenfeld.
No time was given for when the lanes might reopen and social media posts show that traffic has backed up all the way into El Cerrito and Berkeley.
Traffic is being diverted off of the highway at MacDonald Avenue.
The San Pablo Ave. exit was closed shortly after 3:40 p.m. Thursday afternoon.
Stay with ABC7 News for the latest details on this developing story.