It is quite normal for Google to participate in projects not related to Search Engine Technology. Nowadays, Google presents its fully autonomous self-driving car prototype with no accelerator, breaks pedals or steering wheel. It is not the production model yet, but rather the successful working prototype, which could prove very useful in big cities. The car is equipped with a number of sensors, accurately calculating all driving situations and as a result the car could operate safely without human intervention.
The technology could significantly relieve city traffic. For example, you can avoid the tedious parking spot search. Your car can find a place to park without your intrusion, and then pick you up from work in time.
Google's main concern is the safety of this prototype. The car is equipped with built-in sensors, and all immobile and moving objects around the car are taken into account. This allows it to move in heavy traffic without any problems and come around any obstacles. Speed of the prototype is currently limited to 25 miles per hour but Google intends to increase it following some successful tests.