I generally do not run with my driver's license, but I made an exception today so that I could stop and vote on the way to work.
I'm thankful that the drivers that I've met while running have limited their abuse to kicking up huge clouds of dust (though I think this is usually carelessness) or yelling verbal insults. I had not considered the possibility that drivers intentionally targeting runners would be more of a threat than careless or unobservant drivers. Do they swerve toward you, throw things? If the former, I hope that the intent is to scare and not to hit.
Though I have never had any threatening incidents while running that I think were intentional. I did have an incident while walking home from school once. I was walking home from junior high — passing the high school. As I walked on the one road in my route without a sidewalk, I had noticed how cars swerved around me to give me lots of space. Then, one car didn't. I noticed that they were acting differently well before they got near me and was very alert. As they approached, the passenger door flew open and I jumped out of the way. If I hadn't been paying attention, they would have nailed me.
I definitely agree that awareness of our surroundings is our best defense against either accidents or assaults while running.
I have considered a head lamp or a belt lamp, but the times that I have felt the need for one have been rare enough that I've never acted on it. Generally, the moon or the glow from the city illuminate my route well enough for me to avoid the potholes and I especially enjoy running under the moon. It is likely that I will turn off the front lights on my vest when there are no cars and a good moon in the sky.