We're plummeting headlong into a future of cars that move without us, and you may not have to buy a brand new ride to be a part of it. You see, a startup called Cruise has been showing off a working prototype of its aftermarket RP-1 kit, and it aims to bring self-driving smarts to the car you already have.

Cruise's system is an awfully neat one: it combines a roof-mounted sensor array with a series of actuators that manipulate the wheel and pedals. Meanwhile, a computer lodged in your trunk sort of sits between the two, chewing on all that road data and issuing commands to the control system. Of course, all of that is invisible to the person in the driver's seat -- one touch on a button installed in the dash toggles the whole shebang on and off. Calling it a full-fledged autonomous driving system is a bit too generous, though. At this point, it's best to think of it as cruise control plus -- Cruise will maintain a set speed and steer to avoid obstacles, but you shouldn't plan on taking any naps in the back seat.

If all that sounds just a little too good to be true, well, you may be right. Neat as the startup's tech is, it's only set up to work on Bay Area freeways and with Audi's recent A4s and S4s... for now, anyway. Tackling the former is an especially tricky issue since Cruise does all of that road mapping itself; scaling beyond a few locales would likely require loads of time and devotion. Cruise's tech will set you back a pretty penny, too -- it'll cost you $10,000 to trick out your Audi with the requisite slew of sensors and silicon. That's hardly the most accessible proposition we've ever heard, but if the Cruise team keeps the improvements coming, this just might give Google and its rivals a run for their money.