Driverless cars are all the rage. And why not? According to figures, self-driving vehicles are not only safer than human drivers, they're better for the environment too. There's only one problem… and it's kind of a biggie. Driverless vehicles aren't legally available to buy yet, plus even if they were, you'd still have to buy a whole new car, which kind of sucks.

If only there were a way you could retrofit those self-driving smarts onto your current-generation automobile. Well, it turns out you can, thanks to the brainpower of one techie startup. The RP–1 by Cruise is an 'aftermarket highway autopilot' system that can be installed into current vehicles, turning your old jalopy into a 'personal chauffeur'.

The RP–1's onboard computer, roof-mounted sensors, and integrated motors take care of steering, acceleration, and braking, which mean you can just sit back and enjoy the ride. Much like any other self-driving car, you're still legally obliged to sit in the driver's seat in case you need to take control of the vehicle, but provided the system functions correctly, that's the limit of your involvement.

If it sounds too good to be true, it's time to become acquainted with a few significant caveats in the RP–1's tech specs. First up, it's a 'highway autopilot' system designed for major expressways. In other words, it's smart enough to control your vehicle's speed and make lane changes once you're out on the highway, but it doesn't provide fully autonomous control on other kinds of roads. You'll still need to reverse out of your own driveway (the ignominy!) and handle the vehicle on any regular roads.

Plus, the RP–1 only works in California. Sorry, everywhere in the world that isn't California.

But the biggest drawback with this otherwise-amazing-looking add-on? Well, the real killer is that the RP–1 is only compatible with 2012 or newer Audi A4 or S4 models. Remember that bit a couple of paragraphs back where I said it would work with "your old jalopy"? Yeah, well that's 100 percent technically accurate… provided your old jalopy is a 2012 or newer Audi A4 or S4 model. A disappointing limitation, sure, but that's where the tech is for now at least.

What really does give us hope about the RP–1 however is that Cruise is busy working on making the technology compatible outside California and with a wider range of vehicles. So if you've got a spare US$10,000 and you're not too worried about the (potentially very real) dangers of being an early adopter, you can sign up for Cruise's email waitlist right here and be the first to know when the RP–1 will work with your ride.

Just make sure to carefully investigate the legality of self-driving motoring in the country where you live, as the laws in this area, like the tech itself, are very much a work in progress.