Many tort cases are characterized by two interrelated elements: “role uncertainty”, which occurs when individuals take precautions ignorant of their roles in future accidents and availability of “dual-effect precautions”, which reduce both the probability of an individual becoming an injurer and the probability that the same individual will become a victim of someone else’s negligence. In this paper, we extend the traditional model to account for role-uncertainty and dual-effect precautions. We find that in these situations, the traditional formulation of Negligence fails to incentivize efficient precautions, inducing excessive role-specific precautions and insufficient dual-effect precautions. For such cases, we argue for a modification of the standard of due care that accounts for the full benefit of dual-effect precautions, in order to incentivize efficient precautionary efforts.