There will be all sorts of factors that that could be brought up in a civil suit because you are dealing with driver perception.
The could argue the width of the road, whether any of the curves were super elevated, the horizontal geometry was to straight, or not enough signs on the road to warn or provide the driver with information to make his decisions. Again it will be all about driver perception...
Here in Washington State the Supreme Court just ruled in favor of a drunk driver who went of the road and hit a power pole because the power pole was too close to the road.