Road Rage on 99W

I must say, the Oregonian drivers I have experienced have proven to be, overall, the kindest and most courteous of drivers.
Thus I was pretty darn taken aback when I found myself in the front row seat of an unfolding road rage incident. It started innocently enough, a fire truck in full lights and sirens appeared in my rear view mirror. I, along with my fellow drivers, pulled off to the side of the road to let it pass. After the truck went by, well, all hell broke loose.
As I reentered the highway, a large SUV streamed past my left, well past the appropriate side of the road. Simultaneously, a small silver car sped up, barreling down my right side. Immediately I became somewhat confused and concerned as I'd never witnessed reentry on both sides of my vehicle and with both cars at higher than normal speeds. My pulse raced and I started to panic as the white SUV quickly cut in front of my and pulled off partially on the side of the road.
He was attempting to cut off the small silver.
The white SUV driver jumped out of his car, obviously angry as per his aggressive body posture and the look on his face. He held up both fists and was beckoning the small silver car to pull over and for the driver to get out of his vehicle.
The small silver, which had to slow to avoid hitting the man, maneuvered and quickly sped away as the angry man reached back into his white SUV.
I became incredibly scared at this point. I wasn't sure what he was reaching for in his front seat. As the silver car passed him, he jumped back into his vehicle and pulling directly in front of me, appeared to give chase.
I was positively terrified now. The situation, a normal, every day situation that I have frequently experienced in the most inocuos of ways, had become unpredictable, frightening and potentially dangerous.
I slowed way, way down in order to give the angry car more than enough room between us. I wanted to cry yet keep a logical eye on the situation.
A red light proved to put an end to the chase as the silver car had passed the traffic signal before smartly stopping the angry car.
I had an appointment to go to, otherwise I simply wanted to turn around, return to the safety of my home and cry.
I proceeded cautiously and slower than usual as I was well aware that I was in a panic state.
That was yesterday. I still feel my anxiety rising as I write. I haven't fully diffused the incident, so I blog.
There's a mishmash of emotions regarding this that I continue to sort out. The jockeying of fast moving vehicles, (emergency vehicle lights elicit a new, troubling set of feelings) the face and aggressive body posture of an angry man, the confusion and panic will need some time to settle.
I think it is both my CPTSD, triggers regarding angry abusers and my Autism, unpredictable and chaos around me, that are contributing to my unsettled frame of mind.