This strikes me as ripe for abuse.
The QR codes would contain very little information I would imagine but rather a key that is used by the car as an argument for further operations. Leaving all the directional data on the road would be way too easy to abuse.
"it might link to a parking garage database of which parking slots are open"
Imagine creating a QR code, (or copying one that already exists) which tells the car to fetch information from http://your.competitor.example.com/. Then imagine going out late at night and sticking it on a busy motorway.
DOS by traffic.
Also. You better hope that your car doesn't have any vulnerabilities that can be abused by a specially crafted QR code, or by fetching specially crafted data that a QR code prompts it to fetch.
Could you not have the QR codes generated against a private key and the vehicle verify it against the public key to determine whether the instruction came from a trusted source?
Just because it's plain text data in a QR code doesn't mean that it's inherently ripe for abuse.
How could people resist creating a loop of instructions...
Yeah. The obvious first idea is to sign the codes, but then when the private key gets stolen (100% certain to happen sooner or later,) you have to repaint every road.
Strategically speaking the optimal case is a patent to cover the process of sending directions to a car, including everything needed to request them, using any means.
Everyone who produces cars will have to implement some form of that at some point to stay relevant, which makes this a very valuable patent.
Technological hurdles aside, the catch-22 situation is that without much evidence the technology works there will never be public acceptance and legislation for it to be used on the roads. Perhaps Google plan to initially market the system as some sort of beefed-up parking assist - one where you leave your car at the entrance to a car park and collect it from there later. I'm not lawyer, but car parks != public roads, so different laws should apply.
Obviously, nobody would pay loads of extra cash just for that feature, but maybe Google would be willing to subsidise it in the hope that it gets them over the public-acceptance hurdle as people would start getting used to cars driving themselves around without incident and start to trust the technology. It would also build up thousands of hours of evidence of the safety of the system, which the legislators are going to want to see before they okay it for general driving.
Personally, I can't wait until self-driving cars are a reality. It's going to revolutionise transport. :)
Could be a potential way to bring it to market that keeps the insurers happy though. Make the driver 'promise' to pay attention and should an accident happen and the driver didn't take over then the insurer doesn't pay.
