I've been on all four-lane roads in the city and surrounding suburbs. In a city the size of Jackson, that shouldn't be too hard to do. It'd be much harder to do in a place like New York or Los Angeles. I've also clinched four-lane roads in Hattiesburg, Gulfport and Biloxi.
Locally, around Will County, I think I've been on all the 4+ lane roads. Of course, with widening projects, this is in flux.
Fairly certain I've clinched any four-lane or greater road in the Reno-Sparks area at some point in the last decade. I know I haven't done it for the Vegas area, and am not even sure how close I would be to doing so.
I'm in an area so remote that the nearest four-lane road I have not been on is over an hour away from me.
Sidney and Potsdam: Yes; It's kinda hard not to, unless you live under a rock or try to avoid doing so
Rochester: I'm honestly not sure; probably close, though. I know I don't have Mt. Read Blvd and parts of NY 104 out west; I'd have to think about it more.
Heh. Forget four lanes, there aren't too many dead end side streets in Stamford I haven't been down.
Just clinched all the four lane roads in Brevard County with the Pineda Causeway Extension and Palm Bay Rd.