I've had similar situations. It's quite possible that the driver did see you,he just completely misjudged your speed. I've had them look at me,hesitate,then pull on me. They see something and stop/slow as an instinctive reaction,then realise you're a bicycle and figure you can't possibly be going at any serious rate of speed,and pull out thinking they have plenty of time.

Bombing hills with intersections/turnoffs sucks. We've got a couple bad ones around here.