I commute by bicycle two or three days a week when the weather is nice. It is about 11 miles each way. It takes me about an hour each way. Only 10 or 15 minutes more than riding the subway. About 8 miles of it is on the Mount Vernon Trail. It is a well designed and maintained pedestrian and bike route that runs along the Potomac River. It is technically a National Park. The National Park Service posts a set of rules for cyclists. On the list is the requirement that the bike have a bell or horn to warn pedestrians. For a couple of years I had a simple bell, that no one seemed to hear. We were in a bike shop a couple of weeks ago and Jay came up behind me squeaking the cutest horn, shaped like a Panda. People notice it and no doubt remember the fat middle aged man with the squeaky bear on his bike.