Be happy your son will take ride with you and talk to you.
My D got back home wearing only shorts during winter breaks. One winter she walked out to see a friend while it was snowing. I drove out and asked her to get into the car. She told me because I did that, she would take the longer route to walk. There was nothing you could do. As long as it is not a matter of life or death, I don't even say a word now.