Yes you pulled up sharp, which was pretty daft and for an even dafter reason - but not only as others have said should he have left space, but he should have seen the red light just as much as you did.

Well done on keeping fairly calm though. Last time I got rear ended I had a total sense of humour failure and one or two expletives may have been directed at the other driver as I got out. Mind you, it was the second time someone had crashed into my car within the space of an hour ( with someone else having already done the front whilst the car was parked up)

i had a rear end mid last year at a one way bridge 15 mile from where i live was a very wet day , was slowing down as i was on the give way side and at the last minute seen a mondeo come straight at me so slammed the brakes on and next thing i know my daughter says "this car's going to hit us" and starts screaming like a pig and sure enough BANG! so got out and the car that hut me was my cousin couldn't belive it, he gave me £100 there and then to save going though insurance and the damage was very light not even a dent just a big scrape and his car just had a dent and the number plate fell off, was very sorry and was mightily embarrassed but the car got fixed the week later and looked as good as new

For some reason this has me quoting my own post without comment (which I didn't do) and won't let me edit.

I have this after much research, thinking it's not a lot to lose if it's no good.

http://www.aliexpress.com/item/FULL-HD-1080P-Car-DVR-CameraIR-Dashboard-Vehicle-Black-Box-GS1000-Video-Recorder-Free-Shipping/624089952.html

VERY impressed with both video & available features/settings. Plus it's cheaper now!