Help with tenant shared driveway

[Jared York]

Hi all, my tenant is having some issues regarding his shared driveway, and I am hoping to get some advice on how to help him out.

There really isn't any street parking, it's a tight street. 

The driveway is 'Y' shaped, very narrow from the street to the back, then both houses have their own parking area in the back.

The issue he is having is the other homeowner is 'accidentally' leaving nails, screws, and other puncture problem items on the driveway with alarming regularity. This causes obvious problems for my tenant with a lot of tire punctures. 

He has already confronted him, but the other guy seems to not care that much.

He uses a magnet (pictured) every time he enters or leaves, but still ends up with punctures.

Is there anything that can be done?