Fascinating. However, I have one concern. Just as small one. When the escalator is stopped to allow the wheel chair to be mounted on it, if there are passengers already on board, they are going to pitch forward. I think of this because I worked as a sales clerk in the sporting goods department of a Montgomery Wards store while in prelaw, and was carrying a weight set (the box of weights on my left shoulder and the bar in my right hand) on an escalator when some brat without warning hit the emergency stop button. I had no option but to release the bar and grab the handrail with my right hand. The bar almost speared the kid as it sped down the escalator. I suppose attendants will stop the flow of passengers and not stop the escalator until all passengers have dismounted, but that is rather inefficient, isn't it?