The vehicles are not a health or safety issue, any vehicle can attract vermin, one with windows open that have food in them which many people do. They are not abandoned is they people still reside there. Now if the home has been unoccupied for a long time that would be different. How about talking to your neighbors about putting a tarp over them or buying a couple of cheap ones and offer it to them. The cars are not hurting anyone or their property value this is just nitpicking. Have you asked the owner what the reason may be or if there is anything you can do to help them?

Currently under the law if the owner of the vehicle is able to inflate tires or charge a battery or the such the courts have said this is not disable and can remain on the property.

Neighbors have spoken to the owner, he refuses to do anything with the vehicles.
According to the State of MI, a vehicle can be considered abandoned if they do not have current registration plates. Neither of these vehicles have current registration. According to the City of Lansing, an inoperative vehicle is a vehicle that not equipped with all parts that are required to legally and safely operate on public streets and/or cannot be driven under its own power. An inoperative motor vehicle on private property must be stored within a fully enclosed structure completely out of view of the public. I don’t know about the mechanics of either vehicle but the tires are rotted on both them, making them unsafe to operate on public streets. A tarp is not a fully enclosed structure.
The fact that the vehicles harbor an infestation of vermin IS a health issue. Vermin carry all sorts of bacteria, viruses and other diseases that are a threat to everyone. An occasional vehicle with its window down and food inside does not cause an infestation.
We recently had our property evaluated and the appraiser told us this house was indeed lowering the value of our property. He specifically mentioned the disabled vehicles and overall curb appeal of the house. No one wants to look at that and it will deter potential buyers. All the other neighbors in our area take pride in the appearance of their house. This one is a blight on the neighborhood. The over grown trees/bushes/weeds is a different issue and is being dealt with separately.

I think Carol addressed this issue very clearly with the legal aspects. So it seems if a car in your area has tires that are in really bad condition you are going to go after them as well. I guess if it's vermin infested the best way to prove this is with Pictures that will provide the proof that is needed to address this issue. You will have to have documentation there is a real health hazard. You may want to provide documentation from a reputable appraiser one that is not a friend or family member from you and your neighbors to prove that your value of your homes are be dropped considerably by this one home. By the way you address this It seems you have a person issue with this homeowner. Neighbors Trees that are big and bushy is not a reason to say this property is an issue. You may like your property done one way but this does not mean the person in you area has to d it just like you. Trash, over grown grass, weeds are another issue.

I know the owner and he has had a lot of health issues and the wife is disabled. The one car is the only concern since the old car does have plates on them and is a historic car. he has told me he wants to sell the one car and will be doing that ASAP. So please be a good neighbor and try to help instead of blasting him...so far I have asked him if anyone has tried to help and he said not really.

I have been following this post as I live close by and walk the area. This last comment has me wondering. He says one car is historic, yet it looks horrid. It does look like it has not been moved in years. They should consider selling that to someone who will restore it. That being said, I wish them luck.