He was attempting to turn from one road to another, in reverse. That could be interpreted many ways. It was written up (traffic citation) as improper backing. It could have also been written up as entering the road illegally, because it was not a legal turn from one road to the other. You can't do that legally, in reverse. If either road in question was also a state highway, it could have been illegal reversing on one or two different roads, also.
Overall, I'd say that the cop on scene probably wrote up the easiest of the charges he knew off the top of his head . . . improper backing. This garbage truck driver could have been issued a whole PAD worth of citations, though.
But his horrible driving still doesn't explain how the bicyclist rode right into the back of the garbage truck. Maybe the truck was where it wasn't supposed to be, but IT'S A GODDAMNED GARBAGE TRUCK, fer chrissakes!!! Even in a dense fog, it would be tough to NOT avoid hitting that sucker. You'd have to have at least 10 or 20 seconds of warning that it was near, even if you were legally blind. They aren't exactly quiet vehicles. How far do you have to pedal to get out of the way . . . 10 feet maybe? (leaving a comfortable margin) -Dave