In another, our guess was that he was passed out (a peasant, on a four-lane rural highway in Yunnan), but on a road so busy that he was certain eventually to be hit.

But when he reached a four-lane highway with gentle curves, good visibility and little traffic, "I just about fell asleep and ran off the road... Lulled by safety, I'd acted more dangerously."

This paper focuses on characteristics and progress in research of four lane road tunnel. Some key technological problems to be studied are pointed out.