Equity concerns in transportation infrastructure protection against sea level rise

Waterfront communities are facing unprecedented challenges with global Sea Level Rise (SLR) becoming a reality. The households in these communities are likely to be inundated, and inundation of links in the urban transportation system will bring more interruptions to the communities. Some residents will not be able to access their workplaces or education if the transportation system is interrupted. Among these waterfront communities, many are considered disadvantaged communities that have concentrations of minority and low-income families. Residents in these communities are more vulnerable because they tend to be less able to relocate to other neighborhoods with lower risks of SLR. Many of the proposed protection strategies against SLR are at regional levels, and their goals are usually to achieve the greater good for the whole region. However, the distribution of the benefits or burdens may be unequal across different communities. The present paper utilizes detailed hydrodynamic simulation and activity-based transportation simulation to quantify the impact of potential protection strategies on different communities. The San Francisco Bay Area is the geographical region analyzed. Important insights from the analysis are obtained: the improvements of accessibility and mobility, resulting from protecting access to the Bay-crossing bridges, are often greater in disadvantaged communities than others. However, many of the disadvantaged communities located next to the entrances to the bridges are negatively impacted. Additional measures should be taken on relieving these communities to reduce transportation inequality.