Yes, I do believe it's possible to change it...like you I have had premonitions that came true (also involving a car accident) and so I always pay attention when they happen and take measures to avoid them. Sometimes it means I have pulled over and waited for 5 mins before continuing, other times I have altered my route (if i had a strong feeling about a particular intersection). As to whether these notions were premonitions or just 'thoughts' - well there's no way of knowing for sure.

The interesting thing about the car accident that *did* happen was throughout the whole episode I had this compelling feeling that it was a karmic event of some sort - there was sometime soooo familiar about the other driver, and the name of the car's owner. So much so that instead of calling it 'the accident' I started calling it "a karmic intersection" instead.