We built our control systems using a few motors, potentiometers, a Compact RIO embedded controller, and LabVIEW. We then set up wi-fi communication so we can drive the car from an iPhone as well as from a modified Power Wheels truck. For detailed plans, parts lists and code available for download, check out our website.
Motors ripped out of the power windows and attached to wrenches control the gas pedal and the brake. Another motor attaches to the steering column via a bike chain (completely safe). From there it gets so complicated that I just sat back and nodded like I knew what was going on. Then, when I’m just about to scream, “Get to the awesome!”, they totally do. There’s only one thing missing from this video: