Not really a red flag but startles me

My boyfriend is really really nice and sweet. I don’t think anyone I know has been nicer to me, except my grandparents. He does have a habit of road rage though. Not bad, but when someone drives like an idiot, especially at one semi-dangerous intersection, he will very loudly cuss at them(no horn, just swearing). And I have some childhood trauma from abuse so violence or violent behavior like yelling scares the shit out of me, especially when it’s sudden. And he always apologizes to me afterward even though it wasn’t directed at me and I haven’t said anything about it. It just freaks me out a lot, especially since I’m like half asleep during the ride home from school, and i don’t know how or if I should bring it up.

Anyway, this is just a rant so if you don’t have anything nice to say, scroll on. If you have advice, you can leave it.