Having cars that drive themselves can help people in many ways. If the cars are well designed, there is minimal chance of accidents as the cars never get tired and are always fully aware of their surroundings. They can drive more efficiently, reducing gas mileage and they can reduce parking costs and the need for more cars as it has the potential to drop on person off and then go pick someone else up. If they interact with other driverless cars, they can become more efficient as it reduces stop and go traffic from forming. Although there is much good that can come from them, there is always some drawbacks.
First, there may be some bugs in the system and there is a risk of the software being hacked and manipulated, especially if the car is communicating with other cars or is network connected. There is also legal reasons, since the car maker of autonomous vehicles are the ones at fault in an accident, it is really hard for them to release more since they can't afford the potential for a flurry of lawsuits. Google proved they worked and for logged 10's if not 100's of thousands of miles, but sadly until more of the legal stuff is sorted out, not much can be done.
These cars could greatly increase the mobility of certain groups, such as the elderly and children who may not be able to go somewhere as they aren't able to drive. Calling a taxi is one option as well, but as many people prefer car ownership, owning your own car or sharing it with a car sharing program can make more use of the car while cutting down costs. As well, owning one autonomous car can cut back the need for multi-car households, as the one car can replace multiple other ones.
Besides commercial vehicles, most vehicles spend the majority of their time turned off. Just think how much better it would be to not only cut down on the amount of cars on the road and reducing congestion, but cutting down on the costs of owning a car as well.
