摘要：Climate change places additional stress on critical infrastructure systems as demand for resources (e.g., water and electricity) increases and environmental disruptions (e.g., flooding and wildfires) become more frequent and severe. Interconnected infrastructure systems may be particularly vulnerable, as disruptions in one system can cascade to other systems and increase the severity of impacts. To ensure continued functionality, infrastructure systems must be designed or adapted to account for changing environmental conditions, with consideration for the interactions between systems. For this study, we examine the dependencies between shoreline protective infrastructure and transportation infrastructure in the context of sea level rise in the San Francisco Bay Area. Shoreline modifications implemented in one location can cause hydrodynamic feedbacks that exacerbate flooding and associated disruptions elsewhere. On the other hand, the decision not to implement shoreline protection can cause local flooding of roadways that leads to traffic feedbacks and system‐wide travel delays. We compare the magnitude of these feedbacks, in terms of vehicle hours traveled (VHT), across a range of county‐level shoreline scenarios to characterize the effects of one county's shoreline adaptation decisions on its neighbors. Our results show that VHT increases by as much as 7.2% due to hydrodynamic feedbacks and 10.7% due to traffic feedbacks. Comparing these effects for each scenario allows for targeted decision‐making about adaptation approaches that account for both the local effects of flood disruptions and the regional network effects driven by infrastructure interactions. Plain Language Abstract As sea levels rise, coastal communities are considering how to adapt their shorelines to protect themselves from flooding. When one community builds a seawall to protect itself, it may cause increased flooding for its neighbors. On the other hand, if communities do not take action to protect their shorelines, flooding of critical infrastructure systems such as roadways will occur, forcing drivers to find alternate routes. This can lead to longer travel times locally, for drivers who typically use the now‐flooded roads, but also regionally, as these drivers are forced onto other roads that may not have enough capacity to support the higher traffic demand, thus causing additional congestion. In this analysis, we apply a set of computational models to examine the impact of shoreline protection strategies on travel times in the San Francisco Bay Area. We find that travel times can increase by as much as 10.7% for the scenarios considered here, leading to longer delays for commuters.
