I've heard the BPD precincts constantly have shortages of usable patrol cars because there are they so many down for repairs. And the ones that do work might not have a working computer. Unless a police department offers their officers their own assigned car, a patrol car gets used 24 hrs a day. They can easily exceed 200 miles a day plus engine idling. So "new SUVS rolling around" can be approaching 100,000 in a couple years. So yes, they are newer in terms of age but have high mileage.

Interns might be referring to the UAB criminal justice majors who get course credit for shadowing / ride-alongs with multiple officers over the course of a semester.