The actual reason for rubbernecking, is the off-chance that the accident DOES have something to do with you. He saw the lights from his home, so he had higher than average reason to believe that he or someone related may be relevant.
The actual reason for rubbernecking is the exact same reason that public executions were both public and well-attended, often being the social event of the month.
Good old morbid curiosity, we just can't help ourselves.
Biting the hand that feeds IT
