I can only address the Segway, not the others. First, the most vulnerable part of the Segway is the wheels/tires. If one ventures too near anything that can catch, drop, stop, etc., a wheel, the Segway will either try to correct the unexpected motion or totally shut down - and basically both cases will throw the rider off the Segway, sometimes with injury. The maximum speed of a Segway is around 12.5 mph (20 kph), so it can get around at a pretty good clip. But it is not rated for road/highway use! (Scary thought!
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Some cities, malls, etc., have banned the use of Segways on sidewalks and/or streets - equating them to skateboards. Some National Parks and Monuments have also banned their use. There was a recent case where a disabled veteran was using a Segway as a mobility device and was banned from the National Mall in Washington, DC by the Park Service. Luckily, cooler minds prevailed and as the veteran used the Segway for mobility, and he had a permit designating that it was a medical mobility device, he was allowed to use his Segway. However, don't plan riding a Segway along the Rim Trail at Grand Canyon NP! Two weeks ago, due to the winds, it was discouraged to even walk along the Rim Trail!
As a final comment, have you priced Segways? Even a minimum new model is over US$7K - for a single rider! Add a few upgrades, and a few extras . . . well over US$10K.
However, Segways are a blast to ride!
Ron