All five major guest stars portrayed law enforcement officers in previous television series. Angie Dickinson was in Police Woman (1974), James Darren was in T.J. Hooker (1982), Kent McCord and Martin Milner were in Adam-12 (1968), and Fred Dryer was in Hunter (1984).
As an apparent wink to their characters on "Adam-12", towards the beginning of the show Martin Milner and Kent McCord are shown sitting in a police car in their traditional places - Milner driving and McCord in the passenger seat.