The victims' white, four-door 2006 Pontiac was heading east on I-80 between Pinole Valley Road and state Highway 4 when the shooting happened at sometime around 10:40 p.m., Hercules police Reserve Officer Connie Van Putten said.
There were seven people in the Pontiac at the time, including four children.
Van Putten said someone in another vehicle shot at the driver's side of the Pontiac, blowing out one of the car's windows.
The Pontiac spun out onto the shoulder of the highway. Afterward, the driver took the Willow Road exit and stopped at the 76/Circle K gas station, Van Putten said.
The man who was injured was driving the Pontiac, and suffered wounds to his hands, Van Putten said. The woman was in the front passenger seat and suffered a gunshot wound as well as a broken arm, Van Putten said.
Both victims are 24 years old.
None of the four children -- a 12-year-old boy, 8-year-old girl and two 3-year-old girls -- was injured, and all are with family, Van Putten said.
Another passenger, a 26-year-old Richmond man, was sitting in the back seat and was uninjured, Van Putten said.
The two injured victims were taken to a hospital, and are expected to survive, Van Putten said. The woman underwent surgery.
Van Putten said police do not yet have a description of the shooter or the suspect vehicle. The motive for the shooting remains under investigation.
Part of I-80 was closed briefly while police investigated the incident, Van Putten said.