Hi Nugget, welcome aboard. Nugget, what can I say... your gonna have issues with getting in a truck for some time, and may even pass to when your driving your car also... wait and see I guess. You do have two distinct issues, and in fact the final catalyst could have been the suicidal person running in-front of the truck, which just boiled over the pot with the previous life trauma... although a friend of mine got PTSD from killing a child in similar circumstances whilst on operations, so being in that truck could very well just be a major issue by itself. Your doctors and yourself will know the answer to that one.
Working with PTSD is not an easy task, by any means. Many try, with very very few that actually succeed. The common way for people to work with PTSD, is that they often throw themselves into it 150% and become workaholics, which is another method of avoidance, the same as using alcohol in an attempt to suppress trauma. Neither methods work in the long term, both having severe implications upon your health, and basically just putting you years ahead into the grave.
Well, I will be honest with you now about your work situation. Chances are, your going to end up on a pension due to work related illness, as PTSD is classified as a disability to a point to warrant pensioning and some other aspects of disability. Yes, it is that severe. Saying that though, because your job entails driving a truck, which often would allow you to be by yourself and do your own thing, that would fit into your capabilities whilst having PTSD, with its symptoms. The problem though, is that the other factors of PTSD could be the driving stake that cause you not to be capable of even driving long distances anymore, being the concentration, dissociation, etc etc. Being alone is generally what us with PTSD do the best, in the best interest of ourselves at times... so inter-state type driving would fit us all to a degree. The problems stem in those other areas though, and then the other problems is dealing with employers, attitudes, people in general really.
Anyway... welcome aboard, and I look forward to chatting with you more.