that your problem is less a question of easement than it is of zoning. Now there's zoning, and then there's Zoning, if you know what I mean. I have some questions about your situation. Where I live, when someone refers to the "county" in the way you have in your clarification, they generally mean that it's unincorporated area surrounding a nearby municipality within the same County. I don't know if that's your situation or not. It may or may not even matter. But here are some things to think about.
1. In unincorporated areas it is not uncommon to see "zoning" limited to identifying that "here is agricultural," "here is light industrial," "here is residential," etc. As opposed to what I think of as Zoning--within incorporated areas, which very often includes things like setback requirements (from the road, from the adjoining property line, from the neighboring house, from the sidewalk, from the ....), can include rules about signage, color, materials, garbage, junk cars, etc., depending on where you live and how persnickety they got when they really got going on planning the community. Now, on the other hand, some Counties have been very long-sighted and included such provisions for unincorporated areas as well.
2. You know, I'm sure, whether you are in an incorporated area of a municipality or in an unincorporated area of your County. So, if in the municipality, you want to go down to the Planning Commission, or similar type office for the municipality, and request to view the zoning regulations. In reading these, be on the alert for information on setbacks. They may not use the term--they may simply state that no structure can be erected within a particular distance of the road, sidewalk, etc.
3. You should visit the County Planning Commission for the same purpose if you are in an unincorporated area.
4. While you're at either your municipal building or County building, check out the ordinances on junk cars, salvage piles, garbage collection/accumulation, pest infestations (these often will refer to accumulated debris and hiding places of human creation), and any of the other yucky stuff he's piling up. Watch closely for any type of legislation which makes reference to "NUISANCE."
5. How long your neighbor has been doing this is still of importance, because the County or municipal governing body can also be subject to losing property to an adverse possession claim. If he is using THEIR property in a manner which is adverse to their rightful ownership, and does it long enough, it will become his. I'm quite sure the governing body would wish to know of his use of its land.
6. In reading your clarification, I find I'm in need of another clarification: When you refer to his taking over the roadway, do you mean he is actually building ON the road itself, as if it were just extra land for him (seeing as how you have your own driveway, perhaps he figured, "what the heck"), or do you mean that he is building up so closely to the roadway that it's inherently obnoxious? And the junk cars--are they on the road, or on his land, but lined up right alongside the road?
Once you've done a little research, I'd say you will likely be on good ground to contact the attorney for the governing body where you live--could be the "county attorney," "state's attorney," or "district attorney" if you are in an unincorporated county area; if in an incorporated area--"city attorney," "corporate counsel," "village attorney," etc. They should be able to assist you in several potential ways:
A. If there is a zoning violation, they can file a complaint against him for violating the ordinance. This may be civil or criminal or both. His failure to obtain a "variance" will be one of the things in issue.
B. They may have a nuisance action against him for the junk cars or debris piles.
C. They may wish to pursue a civil suit to "quiet title," which would clear up any questions about whose land this is (this is where the length of time comes in), or simply for trespass in order to kick him off. They can also file for an injunction, requiring him to cease and desist from these activities, and take remedial action to clear what he's already done.
D. They may simply issue him a citation, with a time frame for correcting the situation without any penalty if he does so, and a nice hefty fine if he does not.
If you are unable to interest the governing body's attorney in this situation (which I never can believe or understand when it occurs, but it does occasionally happen), then is the time to hire a lawyer of your own, and have that person seek appropriate recourse for you on your own behalf.
I am now finding myself very interested in your situation, so please post back or e-mail me and let me know what's happening. I sort of keep track of these types of cases. Strange hobby, I know, but I'm a land-use junkie. (It's better than painting brick. That's for you, Jay and Jim!!)