Because deceleration takes time, unless you want to be flattened to the front of the vehicle. The more stops you have, the lower the overall speed will be at which this thing operates. High-speed trains in Germany that can drive up to 350 km&#x2F;h often only average around 120 km&#x2F;h over their total distance because with stops in between you spend a lot of time accelerating and decelerating. And where stops are more frequent you can&#x27;t even reach the full speed since you have to start breaking already before you&#x27;re done accelerating.<p>There&#x27;s nothing inherent in physics that prevents self-driving cars, but unless you  want to jump out of a moving hyperloop pod, it has to come to a stop and accelerate again; and it does so slowly enough <i>not</i> to kill its passengers.