re: Have you/would you ever call your city's code enforcement?

It sounds like he might be doing a remodel which means he probably is supposed to obtain a permit. If there is no sign in his yard with a permit # then that’s the angle you go.

I’d probably start with a conversation asking him if he could move the dumpster to the driveway and if not then maybe park his cars in the driveway. He will probably give you a time line of when the dumpster will be moved. If he does nothing then call.