A loud throbbing hum followed by a series of bone shaking bumps wakes me from a light sleep. I had dozed off with my head against the window and had therefore just received the equivalent of a punch to the face. Rubbing my sore temple, I look up just in time to see the driver's head snap up from his chest. Feeling a sharp veer to the left, I'm temporarily glued to the door of the battered old car as we make our way jerkily back up onto the road, throwing up a huge plume of br