Not completely relevant to UK living, but when I get confused I look at the Spanish versions as they seem to have this worked out:
la calle is the street.
la carretera is the road.
Everything within a city, town or village is usually referred to as la calle and everything outside, going from one town to another, is called la carretera.
Helps me anyway.
But I agree that in English it is really down to the situation and what fits best.