As a pedestrian, it's still our responsibility to make sure approaching vehicles are actually stopped before we start crossing. She did not, or she would be alive.
It's certainly prudent to do so, and any amount of self-preservation says you should, but is not checking if you're about to be run over actually negligent?
Edit: Also, if you as a pedestrian, stand at a 35mph road, at night, and wait for all approaching cars to stop before you start crossing, you will be standing there a very long time indeed.
One legal definition of negligence is A failure to behave with the level of care that someone of ordinary prudence would have exercised under the same circumstances.
If you've established that doing so is "certainly prudent", then I think it's reasonable that not doing so is negligent.
