Bicycle safety expert: Bicycling on the left half of the road is much more likely to lead to collisions with automobiles than is bicycling on the right  After all, in three different studies of bicycle-automobile collisions, the bicyclist was riding on the left in 15, 17, and 25 percent of the cases, respectively
Skeptic: But in places where a comparatively high percentage of bicyclists used to ride on the left, there was surprisingly little decrease in collisions between bicyclists and automobiles after bicycling on the left was made illegal
it does not distinguish between places in which bicycling on the left is legal and places in which it is illegal