Several years back (probably about early 2010), I got a bunch of superhero books in a promotion where the first book in the series was being offered for free on Amazon. One of them was Scott Bachmann's The Paragon of Animals, and I believe another was a superhero book set in Pittsburgh with a person who uses a powered exoskeleton from a military project, someone whose powers come from chemistry, and a guy made out of molten steel. Superheroes are precipitated by a male-looking alien who crashes to Earth, and is functionally invulnerable, super-strong, etc.
One of the first people to run into him is a single mother whose car hits him, nearly killing her. I don't remember if he saves her or the powers kicking in saves her, but she winds up super-strong, and gets recruited by the government, in part to find and stop people who are misusing their powers. I remember an early case involved her being the stalking horse to draw out a rapist with superspeed. Later on, the facility she's with gets attacked. All I remember distinctly of the situation is that people are being killed in the darkness and there are alien beasts roaming the halls.
I don't think that the alien was supposed to be benign, but that the crash left him less than malevolent, more a force of nature as he acts as he wishes and very little can slow him down.
I'm trying to look through my list of books on my Kindle, but there are a lot of them, and I don't recall what the cover looked like.