To define the perimeters of objects, you need a small beam. Like a hand held laser pointer generates. Radio waves CAN be focused to a beam, but not a spaghetti strand, more like a manhole cover. Currently radio frequencies cannot resolve the edge locations of objects tight enough to mimic an average human driver's car control skill. By using video information also, you can get the 'edges' and use radio to range finding and gross orientation, even through mediums that stop lasers.
GM has been collecting geolocation data on millions of cars since well before 2011, I know my 2009 was. 2011 was the year that OnStar did a controversial move allowing the sale of anonymized car location and speed data to 3rd parties. They have more than 100 (1000? 5000?) autonomous cars driving around as I type this, on random roads. GM LIDAR cars covered all major highways in the US and mapped out all the features around the roads already. And Vehicle to Vehicle has been active for about a year already, not only the central networked system. How far along past that is GM? Nobody outside of GM knows.
