Game theoretic approaches for highway infrastructure protection against sea level rise: Co-opetition among multiple players

This research investigates the influence of decision-maker behavior on policies that may be adopted for the protection of highway infrastructure against inundations resulting from sea-level rise. We develop an integrated game-theoretical decision-making framework to represent multiple co-opetitive decision-makers’ behavior and use the San Francisco Bay Area shoreline with a scenario of a 0.5 m sea-level rise as a numerical simulation study. The decision-makers’ objective is to minimize the traffic delay caused by inundations in the transportation network that lies within their geographical boundaries. Each decision-maker should determine where to build levees either only along their shoreline without cooperation or along a shared shoreline within a coalition. In this framework, each competitive decision-maker can consider cooperation to minimize its traffic delay, so its behavior can be defined as co-opetitive. We define necessary conditions for forming coalitions for multiple co-opetitive decision-makers, as well as cost-distributing rules and incentive negotiation processes within each coalition. Our model considers the effects of hydrodynamic interactions, traffic flow patterns changes as a result of inundations, and budget constraints on the costs of seashore protection. The hydrodynamics in the Bay Area are affected by the shoreline protection strategy, and closure of a highway link in one county affects traffic delays in other counties due to traffic re-routing. Thus, protection decisions made by a county have potential impacts on several other counties, and therefore counties must consider other counties’ actions. In the numerical study, we investigate the results of co-opetitive games for a range of funding scenarios. It is shown, through examples, that cooperation among counties decreases the additional delay for all participants in most cases compared to competition-only cases. In some cases, cooperation also reduces protection costs.