As I said above, I have also mused on the possibilities of elevated bike paths. I work in a fairly dense downtown area and live in an older inner suburb, about 5 miles from work. I have approximately 30 stop signs and 8 traffic lights on my way to work, and an uninterrupted, elevated bikeway would probably make my commute easier. There would be extra effort riding up a ramp to the bikeway, but that would be offset by the exercise saving of not having to start and stop so much.

Even so, I see the proposal as overall negative. There is no chance of a bikeway being built above every street, so at best perhaps a two thirds of my commute could be elevated and the rest would have to be at grade.

If the bikeway was successfull, it might become very slow and congested, as cycling is very popular in this city, so people would still have to overflow onto parallel surface routes if they didn't want to contend with crowding. As well the bikeway would attract the least experienced, slowest riders.

If the bikeway had a lot of access points, then riders would have to deal with the inconvenience of continually merging traffic. If it didn't have a lot of access points, then people would still have to ride some distance at street level to get to destinations between the on and off ramps.

There's a justifiable paranoia among some cycling groups, best exemplified by the controversial author John Forester, that the provision of alternate facilities for bikes will lead to us being outlawed on the streets. I don't want that. I want to go wherever I want to go - I don't want to be limited to going only where there is a bikeway, or doing laps in a park.

Failing the provision of a separate elevated bikeway, the street is a far better option for me than the sidewalk. I have to get through almost 40 intersections, and at each of them, I'm safer riding through already on the street, than riding into the street from the sidewalk. I have to cross the mouths of hundreds of driveways - residential and business - and at each of them I am safer riding on the street than on the sidewalk. This is a city where pedestrians are fairly common, so providing them with the proper courtesy of dropping to near their speed would more than double my commute time. Of course, your situation may differ, but it may also be the case that sidewalk riding gives you a false sense of safety since you haven't factored in the increased risks you face at intersections.

Peddlephile, I'm not sure if you're a commuter and if you are proposing the bikeways for commuters, as you seem to focus on other issues like exercise.