I have posted this before, but since we have lots of new members join all the time, I will repost a past experience.
I was on a 3 lane highway and a large SUV tried to change lanes while I was in his blind spot. I have him a quick tap of the horn to let him know I was there. He swerved out a little and then veered aggressively into my lane. If I did not slam on my brakes, he would have smashed me into the median. He then slammed on the brakes in front of me. I changed over 2 lanes and accelerated in order to create distance between us. I also drew my handgun in case he attempted to start shooting at me. He sped up to match my speed and he slowed down when I slowed down. I lowered the window and hand the gun pointed at him, but just below the window. Just then, a man in a white Nissan 300Z pulls in between us and he tells me to "go". The man stuck what I believe to be a badge out of his window. My guess he was an off duty cop who saw the whole thing. There was some traffic on the road so I didn't want get into a high speed chase and endanger others. I feel very fortunate that other guy intervened. I was probably a few seconds away from raising my gun and telling him to back the hell off. I actually had a couple of friends following me a few cars behind and he also saw the whole thing. Despite any second guessing, he said it was totally the other guy and that I did nothing to set that guy off.
The ATF should be a convenience store instead of a government agency!