> "I blew through three intersections and luckily didn't get hit," she said. "I'm now going 25 mph heading toward six lanes of traffic."

Honestly 25 mph isn't that fast. Many healthy cyclists can achieve 25 mph quite easily, although perhaps not for a very long time. If you regularly cycle in places with steeper slopes, 25 mph can be achieved without much effort.

But I think the smallness of the scooters themselves could contribute to a feeling of being unsafe. Psychologically it feels that the object is too small to be able for the user to remain in control. This is in contrast to a bike, when the user simply feels more in control even at a similar speed.