The required approach in an eminent domain taking is determined the the value of the subject property and then the value after the taking.
I would think that this is the approach that I would take on this problem.
If the subject property is harmed in any way, then there will be a deminuation of value to the subject. That would be the amount paid to the owner of the property.
If, on the other hand there is no harm found, (and I can not imagine that would be the case) then you can go to the other approaches mentioned above.
In the problem, I would certainly consider the contributory value to the buyer. You are really working with a (in this case) a very rare commodity. It is the only one in existance that can make the neighbors property have any value. How much should he pay his neighbor for allowing him to collect $60K from his potential custormers?
Also, check around, what are buyers paying per square foot for commercial properties for parking lots, etc. in the community. This is not a residential appaisal, this guy is selling a parking lot. It just happens to be in a residential area. A reasonable amount of that parking lot selling price, less the costs involved in creating it should accrue to the potential seller.
Consider this. The potential buyer has this property which could likely be considered surplus land. It only has value to the tax assessor, and the owner has to maintain it. In order to sell it at any price, he needs to have this property.
Consider that your client really needs a consultant in his decision on what to charge instead of an appraisal. What will the market bear.
Just rambling in the early morning.
Wayne Tomlinson,
Illinois State Certified Gerneral Real Estate Appraiser
Find the units of comparison that