Which Way to Go

You are walking on a long, deserted road with nothing in sight. You come up to a "Y" split in the road and there are 2 people there chanting. There is a sign up above them that says, "One of us always lies and the other one always tells the truth", but you don't know which one is which. One road leads to a town and the other one just leads you further out into a desert. You are allowed to ask 1 person, 1 question. Which one do you ask and what question do you ask?