A Cadillac ambulance was taking an injured. driver away, then Chevy/GMC Suburban ambulance, and then Cadillac ambulance.
Unlikely that CHP and the state of California would allow any of its employees to actually drive in a demolition derby.
The races take place at night. But when switching back and forth to the audience cheering it's bright day when for example Jon and Ponch are seen in the crowd.
In the opening sequence after Jon takes pictures of the car parts, people in the background can be seen looking at, pointing and waving at the camera and crew.
During the demolition derby, ramps are visible behind the cars.
When the four CHiPs are playing paddle tennis, Jon and Bonnie are playing Grossman and the Sarge. Jon, played by Larry Wilcox, yells, "Nice shot, Ran," in reference to the actress Randi Oakes who plays Bonnie.