Given the bumpiness of the road ahead, you might be better off with a crash helmet.

考面前条颠簸的道路，最好还是配个头盔吧。

So the bumpiness, the rising high altitude, and the long duration of these two things made this short distance of the road the toughest.

崎不平的道路，逐步升高的海拔，和很长的持续时间路程成为了最艰难的一。