AA small mistake from the other driver could cause a sideswipe
BYou may need to avoid hazards on the road, such as a pothole, and needs room on both sides to maneuver
CLarger vehicles will cause a blast of wind that can affect your control
There are many good reasons for not staying to the left of your lane - in fact, riders are recommended to stay in the center of the lane when being passed. By staying in the center, you will have plenty of room to both sides for maneuvers if you need to avoid a pothole or swerve. You will also be less susceptible to mistakes from the passing vehicle, and you will be able to better control the wind blast from a passing vehicle or truck.