chapter 5 — see-think-do Vision blocks  Poor road conditions  65 Poor road surfaces are a hazard because they can affect your  traction and steering. Loose gravel, ice or rain can cause you  to lose control unless you’re prepared. Some other poor road  conditions are:  Never pass when you are  approaching the top of a  hill. You don’t know what  hazards may be on the  other side of the hill. Be extra cautious when  anything blocks your view.  What could the driver of  the blue car miss?  Having your vision blocked is a hazard. Some examples of  vision blocks are: Be very careful when you can’t see the whole driving scene.  • a bus that blocks your view of people about to cross the  street • a curve or hill that doesn’t let you see what’s ahead  • a large truck in the next lane  • fog, rain or snow. • a paved road that suddenly changes into a gravel one  • wet or icy patches  • large puddles after a rainstorm. ?