There has been an ongoing debate in my area's local newspaper, regarding biking with vs. against the flow of traffic. A recent incident in which a cyclist was hit from behind, and later died of his injuries, prompted a letter in which another local called for cyclists to bike opposing traffic, so that they could more easily see oncoming traffic and avoid it if a crash was imminent.
Experience, the law, and common sense all say that this is wrong — one would think that everyone knows you should ride with traffic because vehicular cycling is safer. That being said, the debate so far has been almost entirely focused on what the law says, and anecdotal evidence, which isn't enough to convince some people. Does anybody have any references to scientific studies showing actual data on the safety of riding with vs. against traffic? Explanations of why are welcome too, but please include some references or data. I'd like some sources that I can cite in a response showing that cycling with traffic is safer for everyone.