I almost had to use my right to protect myself today....

I was at work today and my truck starting acting up. I was taking it to the Ford dealership that does all of our warranty work. There is a major interstate that is under construction and the onramps are closed down so you are forced to exit to the feeder road in order to get on the interstate. Well i was going down to the stop light when i noticed all of the cars in my lane were merging into the right lane. Then i noticed the police officers were waving everyone over. Well my truck is big and slow. I continued foward untill i was close to the cops and they were getting mad at me telling me to get over now. So i start to make my way over and of the sudden i see the front end of an 18 wheeler right next to my passenger side door. Well this is fairly normal in houston bumper to bumper type traffic. I just thought he like most every was just trying to make sure that no one else got in front of him but me. It happens all the time. So i thought nothing of it and when the light turned green i proceeded unto the next red light. When i checked my side mirror as i always do, The same 18 wheeler was traveling at me at an alarming rate. I braced for impact but he stoped just inches from rear ending me. I look again and the man is climbing out of his truck with something in his hand. Now picture this if you can, to the left of me is a concrete baracade, to the right is another car just inches from mine. I am trapped inside the cab of this truck. I had to make a quick deduction of the situation and concluded that the inside of the truck would be better anyways. Well the man ran to my drivers side window on the baracade and starting bashing something against it. I looked and it was one of those hammer tools that the fire department uses to break open windows. For some reason the window was not breaking but i knew if it did he was going to attack me with that same hammer. I thought quick and found the only object in the cab of the truck i could use, my pocket knife. I took it out of my pocket and opened it knowing that i would have to use it if this guy busted my window. I never took my eyes away from his. I was more than prepared to strike if he busted my window. I did not want to have to end his life, but the blind rage that was in his eyes let me know this guy came up here to kill me or hurt me if he could. I knew that the window was going to protect me untill it was shattered. After that i had to protect myself, Wich is why i decided to stay in the truck.
Also i realized that from the angle he was and with his height he would have to lean into the truck to do anything to me, wich would impare his sight and swinging ability. This guy wasn't going to stop untill either i was dead, he was dead, or another person interviened. So i sat there, knife in hand mouthing the words get back or i will stab you. Eventually another trucker a few trucks back got out of his truck and started yelling at him and they started to argue. When this happened i looked forward and saw the cars in front of me had moved on and i was able to escape this mad man for now. I looked back again and the man was getting back in his truck and starting to move. He then got back into the other lane and went on. I don't know why the window did not break. He was using a tool designed to break windows and yet the window only has a few dents, dings, and scratches. There might be a higher reason for that, but for the sake of argument.....i'll say who knows. In the heat of the moment i did not think of getting the mans license plate number(wich is the first thing my boss asked me.). When i made it to the dealership i had a chance to calm down and really think about what happened. I was stuck in a state of shock for the rest of the day. I couldn't believe that i was actually put in a situation that could have ended with me or another person being killed. Of course, as i have said before, I will not go down alone or without a fight if my life is threatoned and there is no other choice. What i would like to know, from an outside opinion, does it seem like a situation were i would have had to defend my life by taking someone elses? I am very greatfull that i had a chance to get away and did not have to make a quick decision. Again, i did not WANT to take the mans life. but would i have been justified if i would have? I at the time and still belive i would have not had any other choice. I need some feedback for the sake of my own sanity. Don't be afraid to speak your true opinions. I will not be offended. Now i'm rambling about it again.....Keep in mind that when i found another option i took it. I was not looking for a weapons fight.