If the driver was proceeding northbound near Potter Marsh, then the sun would be in her eyes at 10:30pm.  I just drove this stretch of road watching the sun setting at 11:00pm.    Southbound sounds much more likely to me, though, as there is a pullout at the south end of the marsh on the east side of the road that birdwatchers frequent.   Lots of binoculars and cameras and not a whole lot of peripheral awareness.  In my experience, the Seward Highway does not have "pedestrians"-- It has people who walk into the road whilst staring at wildlife or lugging a 6 gallon water jug.  Whatever the case may be, it's an unfortunate accident.   Keep one eye on the road and one on the shoulder!  I feel safer driving the Arm in a blizzard than I do driving on a sunny summer's eve.