ROAD MOVIE

What’s that clip from the 1950s cop series “Highway Patrol” doing in producer David Permut’s new comic send-up of another ‘50s cop show, “Dragnet “? Could he be plugging another pic he’s got in development--namely “Highway Patrol” (the movie)?

Says Permut: “Director Tom Mankiewicz put the clip in as a joke. It makes sense that Harry Morgan (Jack Webb’s sidekick in the series) would be watching an old cop show. When ‘Highway Patrol’ gets released (by UA) next summer, I doubt that the ‘Dragnet’ clip will sell many tickets for it.”

Permut can’t top Mel Brooks’ trick for self-promotion: In Brooks’ upcoming “Spaceballs,” the director has close-ups of videocassettes of--surprise!-- all his movies.