A Velomobile is a kind of bike car hybrid. Some of them havpower assist. Often the power assist is in the form of elctricity and and an electric motor.
Velomobiles are ultra lite vehicles with very aerodynamic bodies. These factors help these vehicles achieve high energy efficiency, either when pedalling(human power) alone, with power assist(electric motor or smal combustion engine), or a combination of human power with a power assist system.
Often, Velomobiles, because of their lite weight and aerodynamic design can comfortably cruise by pedal power alone at 50-60 miles per hour for long distances. With an electric power assist the speed can be much higher and the the distance travelled can be much longer.
Below are three videos deomonstrating how they work.
Video below: Here's a short video of a cool hightech vehicle which I saw in front of the Central Station in Amsterdam. They are called velomobiles. Nice!
Video below: 1 minute video about the phenomena VELOMOBILE
Video below: This is a Stokemonkey electric assist modified and installed in an Alligt Alleweder velomobile. A short clip of the throttle being slowly advanced, showing the motor driving the pedals and rear wheel. The noise is not so much the power system as it is the chain roller resonating in the aluminum chassis.