The correct answer, of course, is "It depends." Around here, roadside orphans are usually just that. But a neighbor recently had a large pine felled in his front yard. A couple huge logs were stacked at the curb. R/W extends about 5 feet back. But it appeared to me these had likely been promised to a sawyer, and destined for lumber; sure enough, they were picked up a few days later. I'm somewhat surprised with Ed Moore's experience. If the road crew weren't aware of such an arrangement, then Ed got lucky; or, they may have been acting with full authority. (BTW, Ed, you mean you could roll some of the smaller logs by yourself
) Sometimes, tree trimmers bring along their chipper and shred the wood at the work site; otherwise, they pay about $35 per ton tipping fee. They know that when you ask, and you don't need to remind them.
Our woodturning club has some contacts with DOT and contractors. We usually get a heads up on major clearing, and have a chainsaw party.
The key to any of these situations is to treat the workers as friends. When I buy gravel, the "official" 1 CY measure is a level bucket on the front-end loader. A few minutes of chat gets me a "heaping tablespoon." Works the same with roadies, foremen, clerks at the Borg, etc. Most people enjoy being treated as real live human beings, as long as you don't waste their time. To scramble Al Capone's advice, "You get more cooperation with a kind word and a gun, than you get with a gun alone."
Joe