Do I ride the Segway on the sidewalk or in the street?
The Segway is sidewalk legal in most U.S. states, but if there is no sidewalk it may be ridden on the street in most states as well. Check these two sources for details: the Governors Highway Association Segway page and Segway’s Regulatory Information page. The Segway is an “electric personal assistive mobility device” (or an EPAMD) and in most states you are considered a pedestrian while on a Segway. Laws outside the U.S. vary.