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 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.