The Segway PT can be used on private property with the permission of the owner, in pedestrian spaces, on footpaths/sidewalks, cycle lanes and roads (but not motorways), and along tracks and trails in most places around the world.
Countries that permit the use of Segway PTs in all or most of these places include USA (the Federal government exempts it from motor vehicle legislation, and 45 States plus the District of Columbia permit use on sidewalks, roads, tracks and trails, and public spaces), Canada, Mexico, most European nations (the European Commission exempts it from motor vehicle legislation, and it can be used in Germany, France, Spain, Italy, Belgium, The Netherlands, Austria, Switzerland, Portugal, Greece, Hungary, Czech Republic on footpaths and/or roads, tracks and trails, and public spaces), and in most Asian, Middle Eastern and South American nations.
In New Zealand owners operate their Segway PT as a Mobility Device, the same category as a mobility scooter or electric wheelchair. Mobility Devices must be operated on footpaths whenever they exist and are reasonably accessible, otherwise along the side of the road with traffic (in which case road rules must be obeyed). On footpaths, operators must ride at a speed that does not endanger others, and give way to pedestrians.
Governors Highway Safety AssociationSegway Laws Online