Our family car rides have turned into chaos with constant backseat bickering

Since school started, our 7-year-old and 4-year-old have been arguing nonstop during car rides, even short ones to the grocery store or park. The bickering usually starts over who gets the window seat or control of the music, and it quickly escalates to shouting and tears. I've tried setting clear rules before we get in the car, like taking turns on the window and music choices, but it rarely sticks once we're on the road.

It's exhausting because I want these rides to be peaceful moments or at least low-stress transitions, but they’ve become a dreaded part of the day. I’ve also tried giving each kid a small toy or snack to keep them distracted, but that only works for a few minutes before the fighting restarts.

Has anyone found effective ways to encourage cooperation or calm during car rides with kids this close in age? What tricks have helped your family turn backseat battles into something more manageable or even fun?