Darwin's Blade by Dan Simmons

A series of high-speed fatal car wrecks – accidents that seem. as if they may have been staged – is leading Darwin Minor down a dangerous road. A reluctantexpert on violent ways to die, he sifts clues from wreckage the way a brilliant coroner extracts damning information from a victim’s corpse. But the deeper hedigs, the more enemies he seems to make, and the wider the conspiracy seems to grow. Before long, he’ll find himself relying on deadly resources of his own inorder to save his life – and those of untold others.