Why do people say "Go down this road" or "Go down this corridor" instead of saying "Go straight"?

Question

I was wondering, when giving directions, is it correct to say "go straight" instead of "go down"? Does down and straight in the context of giving directions mean the same thing?

Answer 1

Most of the time they mean the exact same thing, but if you are explaining to someone to "go down the hill" for instance, you are insinuating that they need to drive down a hill. It's best when giving directions to clarify exactly what you mean by "go down". Go down where? The hill? The corridor? The street?

Answer 2

Both are idioms, which give a more colorful way of expressing something. All languages have idioms.