One thing I discovered in my research is there are two kinds of joints. One is an Expansion Joint where as the wood board or filler extends full thickness of concrete and the other is Control Joint where as the wood strip or filler extends from top down approximately 1/3 of thickness. In my case the later was used and it has resulted in a continious slab of concrete 164 feet long(full lenth of drive). My source says the expansion joint was the correct one to use. Just passing on for information purposes.