I recently got the Lego Mindstorms EV3 kit. I wanted to make a self driving car, but I got stuck on the building part. I saw another question like this, however it was for NXT and had no decent answers. I need to make a rotating disk on top of the robot for the Ultrasonic sensor; otherwise I would need 2 more sensors to avoid hitting walls. Remember that it needs to fit on top of a moving robot, not be a stationary stand! I got the self driving car to work, but because the sensor was not rotating, it could only see in front of it. I do not know if this is possible with the EV3 kit, but if you know how, please let me know! Anyways, thanks for reading this! :D
I don't have a Lego EV3, but I have created a self-driving car with my NXT brick. I found the instructions from nxtprograms.com, but they are for the NXT. (I'm sure that you can adapt them for the EV3 though). The program is also for the NXT, but nxtprograms provides enough comment blocks that I think you should easily be able to build your own program with the EV3 software.
Here are the instructions: http://nxtprograms.com/NXT2/explorer/index.html