I currently use my pedicab in Austin, Texas. As of 9/8/08, it's fully licensed by the city of Austin. Woohoo!
Before we get started, let's define pedicab:
-Check out the Wikipedia articlefor an overview
-Look at Pedaltek's tow-behindfor a good example of the trailer type I built
-Read the comments on my Make posts describing the experience so far (hereas well as here) to hear engineering concerns commenters more intelligent than I have raised
Step 1: Plan and Experience
-What requirements (insurance, permit, etc.) does your local government impose for pedicab companies?
-What's the terrain like in the area you'd like to serve? If there's a mega-hill separating the only 2 popular bars in town, that could be a problem...
-What should you learn before undertaking a project of this size? How much easier would welding skills, etc. make your project?
-Do you have the time and energy to invest in building this?
-Are you confident enough in your abilities at making things to strap unsuspecting bystanders onto your creation before darting into traffic?
And, it's a very good idea to consider gaining some riding experience for another pedicab service before endeavoring to create your own. This isn't like normal biking, no matter how quick you might be on your chosen style of cycle...