Because it was on a country road in an area that he's familiar with, late at night with nobody else around for miles? While I wouldn't condone speeding in normal circumstances, this seems close to ok. Heck, I'd probably do the same thing myself if the roads were smooth and twisty.
Long ago when I was in Canada, I almost hit a ground hog while going pedal to the metal in a go-kart on a go-karting track. I avoided it only by slamming the breaks and going turning the steering wheel all the way round in the opposite direction. I crashed into the used tyre barricade, and the worst part was that nobody believed me about the groundhog; they just thought I messed up while driving.
This is the problem we have. Just because you kill a recluse who no one talks to and no one even knows their name, does that mean its ok to kill them? Saying it's ok to speed just because 'there is no one about' is stupid. How do you know there is no one coming round the next bend, or pulling out of the next junction. It only takes one.