I nominate the I-10 westbound from Jacksonville until San Antonio. The most un-broken, monotonous, ugliest landscape, worst tarmac-ed stretch of road I've ever seen. Not until San Antonio does a bit of landscape start and there gets to be pretty scenery. From Houston to the Atlantic is nothing but pine forest. It's making me nauseous just writing this.
I think this is the purest form of bad. It's horrible even in pristine driving conditions. Uneven seams in the roadway every 50 feet for hundreds of miles. If you catch a gridlocked section it's just that much worse. I think the people nominating california freeways are weighting too much on the human aspect, the traffic. That's not inherent to the roadway. Maybe I'm misunderstanding the question. I'm thinking the "worst drive in america" is something that's hideous even if you're the only car on the road.
Never driven the mentioned Ohio stretch, but I can imagine it would probably rival the I-10 for pure misery.