Originally Posted by erig007

Not so easy. The risk of accident is the product of damage to impact and probability of occurrence. For instance, a plane crash would create a huge damage to passengers but its probability of occurrence is very low vs car accidents. If you ride against traffic the damage to impact will increase due to a higher relative speed but the probability of occurrence not necessarily. Some of the probability of occurrence will increase when the time to react decrease due to the higher relative speed, there is also the increased number of cars that will pass you. But riding against traffic allow the cyclist to see vehicles coming with greater visibility. There is also the fact that now the cyclist can react too because of the added visibility (not necessarily in a good way) when both ride in the same way it's essentially the driver coming from behind who see the cyclist and have to react to avoid the cyclist.
But there is also accidents occurring at crossroads and other accidents like opened car doors...