It is completely unfair to compare motorcycles to bicycles, as Mr. Manders does in his argument above. When taking Drivers' Ed. here in MA, we are taught to also "look twice" for motorcycles as where there is one, there is usually another. In addition, since they have motors, motorcycles and street bikes are able to dart quickly between lanes and "looking twice" helps to prevent an accident between cars and motorcycles. In addition to the large visual cues to tell us drivers that motorcycles are around (MUCH larger than a thin person on a thin bike), they also have loud exhausts which are used as a defensive mechanism to also show drivers where they are on the road. To all bikers - if you are so terribly worried about your carbon footprint, please just take the T AND if you are looking to fulfill your cardio requirement for the day, please just join a gym like the rest of us.