Interesting topic.
A few years ago, I started driving in Durban and never experienced road rage much, to be honest.
However, moving to JHb 6 years ago, it became so bad that as soon as I got into a road rage incident, it would almost always get out of hand by me over reacting and thinking I was the "Traffic police" on the road - instead, I was just a young guy, being an ass.
I used to even stop in front of people and get out... bad times.
However, over the last two years I have calmed down completely. Unless someone forces me to slam on breaks and puts my life in danger, I couldn't care less.
I now just say to myself "That dude is a chop..he will come short.." and "Let it go..."
It's mostly thanks to the So that I have calmed down - she showed me what an idiot I was being as I didn't realize it.
I relized that there is just no point in getting upset over what other people do / don't do. I cannot control it and therefor, I don't worry about it.
It has never gotten this bad though:
http://www.youtube.com/watch?v=gYm9vCPLoG4