As for the spitting case -- get this. The alleged victim actually SAVED THE LOOGIE. But that wasn't enough for a prosecution. The D.A. says it was one guy's word against another, and Justin denied hawking a big one.
The D.A. says during the altercation, the neighbor told cops Bieber said, "I will beat the s**t out of you and I will f**king kill you." D.A. investigators decided Bieber's actions were "disproportionate and immature, but since the neighbor had entered the property without invitation Bieber's actions did not rise to the level of a criminal threat."
As for the speeding case, it all came down to the video tape ... which shows Justin was not even in the Ferrari in question at the time of the incident. He was riding behind the car on a motorcycle.
The D.A. also notes Tyler, the Creator actually took responsibility on TMZ for driving the car. So case closed.