Aside from the obvious stupidity of not paying full attention to the road in front of me, I feel the small wheels on my folding bike really contributed to this fall. Although the bike is super maneuverable and nimble in traffic - the wheels do amplify any movement of the bars and the smaller tires are less forgiving of potholes and any pavement irregularities. As much as I appreciate the convenience of the folder on the train part of my commute - I can (and have in the past) taken a full sized bike on the train for my commute. Both my Gary Fisher and Iron Horse are bullet proof commuters and fit pretty easily in the trunk of my car (albeit with the rear seat down) Might be more prudent on foul weather days and certainly something to consider with more bad weather and winter coming...