Neighbor keeps parking too close!!?

Ok, this is a little juvenile but it's actually happening. Since my neighbor (a section 8 renter) moved in about 5 years ago he's always parked fairly close to the back bumper of my vehicle. Now it's gotten worse, I just went out and measured it to be 2.25 inches. I can't even get in my trunk, I'm not pinned in cause I always give myself some room in the front but it's just a little annonying, you know?

Typically he's a pretty nice guy, except for when it comes to parking...he thinks he owns the whole street!! and he's the newest one on it :-) I've even seen other people park where he typically does and he'll go and yell and scream at them "get the f**k outta my spot"

I know it's even worse when I'm not home and he'll basically close up the spot, I known the minimum dimensions of a paking spot in Pennsylvania are 18 ft by 8 ft. I park in them everyday downtown, and what he leaves is way less, just barely big enough to fit a car in.

I've tried talking to him asking him if he could leave a little more room, he just looks at you like your speaking another language, but if you talk to him about anything else he's perfectly normal.

I'm just wondering what can I do? I'd really hate to bother the police on such a stupid issue, but it's really getting a little irritating to struggle to park my car whenever he gets home first, or to not be able to walk behind my car. I'm just looking to get a standard, average distance between parked vehicles just like everyone else does!!

Thanks for any help / advice in advance!!