Bill,
As some of the posts said, there may be more to it than just some guy ticked off at the speed cameras. The pictures show the car pulling out from behind the van which would tend to indicate that the driver stopped for whatever reason. But even a speeding ticket is not reason to kill anyone.
However I am afraid that you could be right about the violence escalating. Around here it is now a daily thing for robbery, assault, murder, breaking and entering, and about any other crime you can name. Much of the increase in crime right here is due to the very high unemployment rate, easy access to any kind of dope you want, and I apologize to those hard working law enforcement people who do their best, but we do have some crooked cops here and none of the police seem interested in anything but writing seat belt tickets. They will sit and watch driver after driver go by with a dam cell phone in their ear and won't stop them. The police department is already in trouble over their business dealings with a prostitute.
Ron
