Issue 1) In the image below the green outline is what I believe is my property line at my Triplex, and the orange outline is the neighboring businesses L shaped lot which extends behind mine. (We need to have a survey completed to confirm lines, but these are the generally understood lines by myself and the neighboring business) He parks vehicles both in the spaces in the back, as well as that 3rd lane of what from the ground appears to be my driveway. There is a curb between the two, over on his side.

I have volunteered to let him continue using the space in the back, if I could use the driveway space for my tenants. 3 lanes of driveway for a Triplex. But, he will not allow that use as he parks his own vehicle there. If I do get a survey, and work with a tow company to start towing his customers vehicles that are parked there it will destroy any chance of a continuing good relationship. (I have access to his security system as I paid him to have a couple of cameras added to his system facing my driveway and property after some prior issues with a tenant)

Does anyone have any suggestions on how to resolve that parking space issue?

Very related issue 2) One Apt's tenant (my last inherited tenant) never had a car until recently. My lease states while there is a driveway, I do not guarantee parking availability, and there is street parking available to be used where legal. This tenant is now blocking the other tenants in because he is refusing to utilize the (admittedly difficult to find) street parking. His justification is that the previous owner stated that the Tenants who lived there the longest got priority on parking spaces. I explained to him that was no longer the case, but he pretty much told me he is going to continue doing it.

If there is no recourse to solve that issue by using that space that very much looks from the ground to be part of my driveway, how should I handle this? Options I can think of are A) Tell them to handle this themselves... But this may cause tenants to leave as they are getting very upset. B) Paint lines for the 2 lanes I do have. Drop rent by $25, and add a $25 fee for use of a driveway lane, and work something out with a Tow company. C) Potentially bring in Gravel to extend the driveway forward to allow another exit through the neighboring business parking lot. or D) Deal with it now, and with new leases adopt the policy that the oldest tenants get priority, and has the option to pay a parking cost IF there is a lane available. Again this will involve babysitting though and an arrangement with a tow company willing to work with it...