If you find those roads narrow, don't try the UK or (especially) Ireland.

I've driven in France, Iberia, and Central/near Eastern Europe (Stuttgart to Budapest, Krakow, and back). City streets can be small, but the highways are highways. Even smaller roads in Slovakia weren't bad. Honestly didn't seem that different from driving in the US except that obedience to speed limits was a lot higher (though their limits are generally higher, so there's no real need to speed - 130 km/h is just over 80 mph, which is usually as fast as I would want to drive anyway).