Discussion of a few recent prangs and offs here had me thinking on the ride in today (after a nice officer had a chat with me (friendly and no ticket) about cutting up the left of a million cars stopped by roadworks, I then had plenty of time, sitting behind him, to think while popping forward a metre at a time). Here's my simple theory: traffic accident = bad conditions + bad luck + bad decisions on the part of one or more people Much as we like to over-simplify and find someone to blame, it's usually some combination of these elements in some proportion, so the blame could be 70/30 between the people involved, or 90/10... Now in terms of accident prevention, there are several levels: Level 0: Just do exactly what you want to do at all times - you can always blame bad luck if something happens Level 1: Modify your own decisions and make as many good decisions (and as few bad ones) as possible. That also includes making good decisions in relation to the conditions you know about - rain, crap on the road, poor light, sunglare, etc. Level 2: Modify your own decisions as above, but then go the step further to take into account (a) the conditions you don't know about - the cow on the road just around the corner and (b) others' bad decisions: the woman this morning who pulled out of the road on the left, got to the middle of my lane and *then* stopped to look for vehicles in the lane on-coming to me... so she ended up stationary blocking my entire lane. There's always bad luck, and there are always bad decisions on the part of others so catastrophic that they're unavoidable. But a bit of Level 2 accident prevention is always going to be good medicine.