When Mac recounts the story of coming home to find Mildred (Nancy Walker) walking around nude, he says "she screamed and wrapped herself in paper towels" - a winking reference to the Bounty paper towel commercials that Walker starred in throughout the '70s and '80s.
There were several family connections in this production. The director, Lou Antonio, is the brother of Jim Antonio, who plays Dr. Tom Wheatley. Mrs.Wheatley is played by Barbara Bosson, who was the real life wife of Steven Bochco, the Executive Story Consultant for the show. Hildy Brooks, who played Louise Noland, is the real life wife of Lou Antonio.
In two different scenes - first when the rally participants are picnicking by the side of the road, and then again when Mac and Enright are heading to the McMillan's hotel room - Pepsi cans are shown with tape obscuring the brand name. This was done to avoid having to pay licensing fees to the company, especially when it went into syndication. Which is a little odd since everyone would know it was a Pepsi can.
When Sally is driving to scene of the previous accident, she passes a sign identifying the childishly-named body of water as Kakawewe Lake.
The town the rally starts in is named Barkley. Peter Breck (George Noland) previously starred in The Big Valley (1965) where he played Nick Barkley.