Lots of people speed on main roads, that's one of the things about main roads. One of the other things about them is that if people speed there regularly, the police tend to set up their speed traps in those areas regularly, and then the locals learn not to speed there. Regardless, children should not be playing on main roads, in my opinion.
I believe that even the road leading to DM's little road has a bus route on it, so again, children should not be playing on these roads, in my opinion.
In my opinion, taking a grocery cart home with you is not showing off, otherwise homeless people would look way cooler, since they'd have way more to show off all the time. People bring carts home all the time, and they also return them, or other people drive around and pick them up...in their pick up trucks... OMG, maybe That's why DM wanted the Ram, to start a business stealing and then returning shopping carts!