The incident happened at about 2:30 p.m. Monday. Authorities said a black Mercedes and a red Honda Civic were both exiting on the merging Hillcroft eastbound lane.
There was an argument between the two drivers about who would go first.
The driver of the black Mercedes drove around the red Honda Civic and shot into the back of the vehicle, authorities said. The driver of the red civic was grazed in the right shoulder and crashed as a result. The victim was taken to a nearby hospital with non-life-threatening injuries.
The suspect shooter fled the scene, authorities said.