Some are designed like this (St. Augustine's in Ipswich for example) where you approach for straight on in two lanes and are supposed to merge in turn on the exit. Causes no end of fun for the spectator.
Loads like that - like on the A35 here. https://www.google.co.uk/maps/@50.7...101.29578&pitch=0&thumbfov=100!7i13312!8i6656
Very useful for nipping past a slower vehicle.