My father taught me to leave enough space in front of me in case of being hit, but also in case I need to get out of the line for some reason. I've had to get out of line a number of times over the years due to accidents. I have 3 routes I can take to get to work, so once I realize there's an accident I can just turn around and go another way. Works out well, but sure does piss off people behind me sometimes.