Google something called Cooperative ITS. ITS stands for Intelligent Transport Systems. The 'Cooperative' bit refers to cars that interact with the road infrastructure, exchanging data on where they are, their intentions, road conditions and so on. Effectively, every vehicle on the road becomes a probe/source of data, not just a recipient.
Years away? Nah. I was at a conference in Detroit last autumn where GM's head said she'd accelerate deployment onto some roads within a couple of years. The same's going on in Europe.
As to camera systems, you might start by looking at CMOS sensors - the types of cameras you see in mobile phones. A CMOS-based camera the size of a 2 Euro coin could be stuck in a traffic signal post and provide a usable street-monitoring capability. That can easily be integrated into a vehicle and the quality of images your current smart phones can generate demonstrates a base level of image quality that we can expect. The cost point on the vision technology is coming down all the time. The car manufacturers are chasing a cost point in the single hundreds of dollars but it will continue to come down. Moore's Law and all that.
Cost is an issue, certainly. Look at things like the Terramax - the autonomous logistics vehicle that the US Army has been developing - pricey, but iterative generations and volume production will bring that down. That's the absolute top-end - a vehicle that can navigate off-road, rather than just following the road.
But cars such as Mercedes's S-Class already have machine vision technology on board which will allow the car to follow, unaided, the lines in the road, the cars in front and so on. The machine vision technology can pick out of the vista in front of the vehicle such things as road signs, interpret them and act/react accordingly. So the technology's already here for hands-off driving and at a price point that can go into top-level cars. Expect the E-Class to have it in the not-too-distant, and equivalent trickle-down in other manufacturers' ranges soon.
The sticking points are legislative - the Vienna Convention stipulated for a long time that there be a human in the loop. That's been changed recently, albeit on the quiet, but in reality cars such as the S-Class can already effectively drive themselves.
Google might be grabbing the headlines because it's a consumer brand but the mainstream motor manufacturers have been plugging away, individually and collectively through government-funded ITS projects, for years.
So, expect it be around a lot sooner than some of you expect.