Sadly, there's not a whole lot you can do when a small heavy object hits you without time to react. Coincidentally, almost 2 decades ago and about a mile away from this location, I struck a deer with a Miata. Got lucky as the deer struck the front bumper, then sailed over the top of the car.
I know a fella, during heavy rains was driving at night on a dark road and turned onto a road, then drove straight into a flooded section.
Totaled the Sienna, nobody was hurt.
That's why I find I don't like driving at night too many surprises can happen that you don't see until too late.
I would never have guessed their would be deer on the Dulles access road, much less a fatal car accident as a result. Sad to hear. We've hit a few deer over the last five years, and we never imagined it could be fatal.
I always tell my teenage sons driving at night decreases your response time at least 100% because you see only half the distance (Even with modern LED lighting).
In reality it is much worse because our headlights (low beams) are only effective up to 500 ft. If you travel faster the reaction time is much less. LED seems safer but remember - bright lighting tends to obscure the dark areas your headlights do not shine upon (like the areas oncoming traffic come from).