Often times it's loitering charges, loitering being a fancy term for "being out in public whenever it displeases a person of authority". Sitting on a public bench, having a picnic, walking on a sidewalk, sleeping in your car, whatever, all of those can and will get you loitering charges depending on your exact location in the United States.

Then you have public intoxication charges which on paper are only supposed to apply if you're causing a public disturbance (despite disorderly conduct already being a charge for that, public intoxication just makes it more severe), but in reality it's mostly used to harass drunk people who couldn't get a ride home, or uber home, and decided not to drive while drunk. I wouldn't be surprised if you had a higher likelihood of getting arrested for public intoxication while drunk walking/public transporting home than of getting arrested for DUI while drunk driving home. But public intoxication and even DUI can also be used if you're sleeping off drunkenness in your car, while the car is turned off.