A long-standing urban legend suggests that a penny dropped from a great height, let’s say the Empire State Building, kills. The penny should speed up and pass through a person’s skull easily.
In reality, the penny would probably just annoy a pedestrian. Even a penny is limited. All objects reach a terminal velocity when they are in free fall for long enough. They do not keep speeding up.
The problem with a penny is that it is flat, small, and light. A gust of wind or updraft would break its fall. So for anyone who accidentally lets a penny drop from his or her fingers, relax, don’t worry the streets are safe.