I feel the same as you when it comes to cliffs and ledges without rails ... gives me the chills too - its worse if I'm the passenger and can see over the edge. It's a deep seated fear that stems from an incident I had as a child where we were in a jeep and my mother driving it somehow she lobbed us off the side of the road and turned the jeep on its side - all i remember is her saying "nobody move " cause it was teetering on a ledge.In retrospect 0 it was only a small ledge - but as a kid everything seems bigger than it is...I don't like traveling on windy roads either -- especially in the snow or at night.