Another possibility is that he had a nervous breakdown or substance abuse episode, leading to both the paranoid emails and the irrational vehicle operations. Obviously I'm not saying that's the case, but the extremely irrational driving goes fits a theory of paranoid delusions (brought on by any number of mechanisms), just as the hacked car system goes with about to uncover something big.
Or, an even less interesting possibility: Hastings might in fact have been under some kind of investigation; he might have not slept well the prior night; and he might have fallen asleep at the wheel. This is consistent with the facts of the case: the crash happened in the middle of the night, just after Hastings sped through a red light.