http://cc.usu.edu/~bob/bike/where_to_ride.html
Where to Ride your Bike?
Where on the roadway should you ride your bike? Lots of people first guess "on the left, facing traffic" for a variety of reasons. But that first choice is wrong, for a variety of reasons:
According to the League of American Bicyclists' Bike Ed training program, riding on the left side is the leading single cause of car/bike collisions.
Riding with traffic puts you where other travelers are looking for conflicting traffic, instead of putting you where they aren't looking, especially at intersections, driveways and crosswalks.
The closing speed of traffic in your lane is the sum of both speeds if you are facing traffic, but is the difference of speeds if you are with traffic. That difference in closing speed may mean a big difference in reaction time for you and the motorist.
When a wrong way cyclist meets a right way cyclist, who swerves out into traffic or into the gutter? I hope you don't expect me to!
Less than 3% of car/bike collisions in daylight are due to overtaking errors (rear end collisions).
State Law requires bicyclists to ride on the right, not on the left. When a collision results from wrong way riding, you may be found at fault.