It would actually reduce congestion. When I had a car here in SF, in many cases, I spent more time driving around looking for parking than actually driving to and from my destination. This would prevent that since the car could drop you off and head back home or to a nearby area with more readily available parking.<p>Take this idea to the next level, and you can have services like Uber that are run completely by algorithm. These cars can be parked all around the city and as soon as someone requests an Uber, the car wakes up and picks the customer up, after dropoff it finds the most efficient place to repark itself and wait for the next customer. This would significantly reduce congestion in big cities.