Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Civil, Construction, and Environmental Engineering

First Advisor

Douglas D. Gransberg


In 2012, the U.S. Congress passed the Moving Ahead for Progress in the 21st Century (MAP-21) Act, which funds surface transportation programs and transforms the policy and programmatic framework for capital investments to guide the growth and development of the country's vital transportation infrastructure. Within many of its goals, MAP-21 supports the economic growth of the regions and requires each state to develop a Transportation Asset Management (TAM) plan (FHWA-5 2012).

Therefore, the objective of this study is to develop a framework for the Iowa Department of Transportation (IADOT) to help in the prioritization and allocation of the resources such that it supports the local economies, and more specifically, Iowa's Agricultural Economy. The proposed TAM framework is the result of a comprehensive literature review, a case study analysis and several outreach and informal interviews with stakeholders that provided the tools to help identify the user's impact as well as to determine a flexible methodology that could easily be adapted to the current practices and policies of the state Department of Transportation (DOT).

The research focuses the attention on the low-volume bridges located in the agricultural counties of Iowa because recent research has shown they have the greatest percentage of structurally deficient bridges in the nation. Many of the same counties also have the highest crop yields in the state, creating a situation where detours caused by deficient bridges on farm-to-market roads increase the cost to transport the crops. Thus, the research proposes the use of Social Return on Investment (SROI), a tool used by international institutions such as the World Bank, as an asset management metric to gauge to the socioeconomic impact on the state in an effort to provide quantified justification to fund improvements on low-volume assets such as these rural bridges. The study found that combining SROI with current asset management metrics like Average Daily Traffic (ADT) made it possible to prioritize the bridges in such way that the limited resources available are allocated in a manner that promotes a more equitable fashion and that directly benefits the user, in this case Iowa farmers. The result is a system that more closely aligns itself with the spirit of MAP-21 to use infrastructure investments to facilitate economic growth for Iowa's agricultural economy.


Copyright Owner

Maria Catalina Miller



File Format


File Size

166 pages