I agree, but there are sometimes conditions you cannot account for. I was driving on the M4 a couple of Fridays ago when there was torrential rain. I was driving at about 45-50mph as the visibility was so poor. I was alongside an old style mini in the outside lane at this speed when he hit a huge river of water - the mini veered around and sent a massive bow wave up into my lane over my car. It was like a waterfall had suddenly engulfed my car and I couldn't see a thing. The lack of vision probably only lasted a second or two, but that's enough for something dangerous to happen even at that speed. Fortunately I kept control of my car and the mini stayed in his lane. I slowed down even more after that, but was passed a number of times by others racing along as if the conditions were perfect.