So far, the "but it was 55mph and she couldn't stop in time" folks are saying the terrain and curve combined "with the speed limit" to remove her reaction time. I've ridden that road. a 5' tall obstacle is visible from quite a ways from the direction she was going, and some of us are considering a re-construction with cyclists and video to show that.

The 55 "limit" is just that, not a mandatory speed, and is 88'/second. It's very likely she had 4 seconds or more to react. If she was going less than that, she had even more time. I've not had a chance to get over there and look at skids, but I'd bet even money there either is none or they're after impact.