# A Systematic Review: To Increase Transportation Infrastructure Resilience to Flooding Events
## 5 Conclusions  
This review investigated 133 final studies selected through three stages of review process from Google Scholar and Scopus databases from 1900 to 2021. Flood vulnerability is an extremely important topic in research from 1981 to 2021, and transportation is a critical infrastructure sector that needs enhanced resilience during and after flooding events. The years of 1900 to 1980 did not provide many natural disaster vulnerability studies, but once climate change effects were noticed and began to be studied in the 1980's, there was a quick increase. Therefore, after 1981, there are a lot of needs for studies regarding flooding, flooding vulnerability, and transportation infrastructure resilience to flood events. The current stage of research was analyzed by reviewing 133 studies. These studies were all organized by categories that aligned with the Infrastructure Resilience Planning Framework's risk assessment and develop actions steps. There was a knowledge gap noticed within assessing existing resources and capabilities of step 4 and the components of step 5, the implementation and evaluation step. Advancement of studies regarding this could help to raise resiliency of the transportation infrastructure as determined by this review.  
Analysis of flood risk utilizing hydrological and hydrodynamic models as well as spatial analysis is a crucial step towards flood resilience. Flood prediction is also important for investigating flood resilience, as flood depths and extents are an important determiner of transportation infrastructure vulnerability. Additionally, real-time flood models that extend beyond historical flood risk can be helpful towards understanding and recommending flood response methods. Investigation of effects of floods on transportation infrastructure can help create a better visualization of the dangers of flooding and the responses of the transportation sector. Transportation infrastructure vulnerability study can help to understand an area to a greater degree and can help to pivot community focuses where needed for resilience measures and mitigation strategies. Various factors such as social and economic factors as well as accessibility and mobility were included to assess transportation infrastructure vulnerability. Impacted accessibility and mobility were investigated by delay, changes in traffic volumes, and transportation network disruptions. An advancement of assessment of existing resources and capabilities, implementation through existing planning mechanisms, resilience evaluation and monitoring, and plan updating represent the most benefit to increase transportation infrastructure resilience to flood events.  
Conceptualization, G.W. and J.E.A.; methodology, G.W. and J.E.A.; investigation, G.W.; resources, G.W.; data curation, G.W.; writing--original draft preparation, G.W.; writing--review and editing, G.W. and J.E.A.; visualization, G.W. and J.E.A.; supervision, J.E.A.; project administration, J.E.A.; funding acquisition, J.E.A. All authors have read and agreed to the published version of the manuscript.  
This research was funded by USDOE (United States Department of Education) GAANN (Graduate Assistance in Areas of National Need).  
Not applicable.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.