This is a curious one, and not very pretty. However it’s well worth doing, not just because it’s the only road crossing of the Rhône between Loriol and Montélimar, but because of the way it does it. I had missed it till now.
A look at the map shows the road crossing ‘half the river’ at le Pouzet, going about 8km south along an elongated island, then hopping across the other ‘half’ near les Tourettes.
In fact, what I didn’t realise is that both bridges are parts of hydroelectric plants, the bigger one being the one at the southern end. I’ve no idea how much of the island’s existence is down to human engineering (the eastern side of the road has a massive bank, clearly man-made, and there are road barriers close the road, in times of flooding, I assume).
It’s not a road I’d want do frequently, but it was quiet, and with a tailwind, pleasant enough. Though you might find it more exciting if you are into hydroelectric plants, I guess.