Absolute positively the worst road ever

I think the roughest road--at least the roughest for the longest distance--that I've had my motorhome on was the Dalton Highway up to Prudhoe Bay. It was far from the worst road, though; the scenery is second to none, and seeing genuine tundra (with pingos!) was fascinating.

I-84 through New York is pretty rough and often a bit busy and has not too many redeeming qualities in my opinion other than at times being a convenient route between where I am and where I need to be.