Without knowing the road it's difficult to say for sure, but the car driver might be significantly responsible here.

If a pedestrian is keeping as close to the side of the road as reasonably possible and is reasonably visible (e.g. not wearing all black on a pitch black section of road), then it doesn't seem unreasonable to expect a driver to avoid crashing into them - even on a highway. Especially if it's a reasonably straight road which most highways are.