Inya Nlenanya

Infrastructure impacts of Iowa's renewable energy.

This paper investigates the physical and fiscal impacts of Iowas existing biofuel plants and wind power industries. A four-county cluster in northern Iowa and a two-county cluster in southern Iowa were identified through a local agency survey as having a large number of diverse facilities and were selected for analysis of traffic and physical impact. The large-truck traffic patterns on Iowas secondary and local roads from 2002 to 2008 were analyzed and associated with the pavement condition and county maintenance expenditures. A trend of increased maintenance costs in the year after a biofuel plant became operational as well as during the construction period was observed. Large-truck traffic also increased dramatically during the construction period and then dropped after the plant became operational, but not to the levels before the plants construction. The major road damage associated with wind farms occurred during construction activities and predominantly on gravel roads. Face-to-face interviews with county engineers were conducted to validate the observed trends and discuss the limitations of the data. Finally, with an expanded sample of 24 counties, one-way panel data regression models were developed to estimate pavement condition and maintenance costs as a function of vehicle miles traveled, plant capacity and years of operation, corn and soybean production, and soil and environmental conditions.

Risk Management and Data Needs: A State of the Practice Survey of State Highway Agencies

Risk management analysis is one of the new requirements under MAP-21 that separates transportation asset management programs from business as usual for the state departments of transportation (DOTs). Based on this requirement, each agency will discuss the concept of risk and how it should be incorporated into its transportation asset management program as well as how it informs maintenance practices, asset replacement or rehabilitation, and emergency management and response planning. This will require an agency to provide a list of risk exposures and document its system-wide risk management strategy. This paper presents the results of a state of the practice survey of how agencies are developing their risk-based asset management plan and discusses recommendations for future research. The results show that state highway agencies are increasingly adapting the way they do business to include explicit considerations of risks. At the moment, this consideration of risk is not linked to data, and as a result most agencies do not have a data driven way of tracking risk and updating their risk exposures. The significance of the results highlights the need for further research on data driven risk management and to synthesize methodologies for integrating risk assessment into an agency’s decision-making process.

Pavement Condition: New Approach for Iowa Department of Transportation

The collection of pavement condition data is one of the most important and costly elements of operating a pavement management system (PMS). This function is crucial, as business decisions rely on it: a PMS should be able to prioritize maintenance, rehabilitation, and reconstruction effectively. Pavement condition data are usually transformed into a numerical rating system [a pavement condition index (PCI)] that qualitatively describes individual pavement segments or a network. The Iowa Department of Transportations PCI is calculated by using PCI equations that are based on statistical regression analysis. Different attributes are used for different pavement families. The study summarized here aimed to develop a new condition index that provides a consistent, unified approach to rating pavements in Iowa. The proposed system has a 100-point scale that is based on five indexes derived from specific distress data or pavement properties and an overall index that combines individual indexes with weighting factors. The indexes cover cracking, ride, rutting, faulting, and friction. The cracking index is formed by combining cracking data (i.e., transverse cracking, longitudinal cracking, wheelpath cracking, and alligator cracking indexes). Ride, rutting, and faulting indexes use the international roughness index, rut depth, and fault height, respectively. The proposed overall PCI is made up of 40% cracking index, 40% ride index, and 20% faulting index for portland cement concrete pavements and 40% cracking index, 40% ride index, and 20% rutting index for asphalt concrete pavements. The proposed condition index was compared with the current PCI and, in general, was found to offer fairly good correlation.

Bioeconomy and Transportation Infrastructure Impacts: A Case Study of Iowa’s Renewable Energy

The federal government is aggressively promoting biofuels as an answer to global climate change and dependence on imported energy sources. As a result, ethanol production in the United States (U.S.) grew at an annual rate of 32% between 2005 and 2008 spurred on by the U.S. Department of Energy’s goal of having 20% of U.S. transportation fuels to come from biological-based sources by 2030. This will require a dramatic increase in the present levels of ethanol and biodiesel production and distribution and have significant infrastructure implications as transportation of raw materials to the biorefineries and biofuel to markets will not only create additional transport demand but also competition and significant growth in other major freight categories. The present chapter first discusses the physical and fiscal impacts of biofuel plants and wind power industries. Then, using a sample of 24 counties in the north, west, and south part of Iowa, which were identified through a local agency survey as having a large number of diverse facilities, one-way panel data regression models are presented that estimate pavement condition and maintenance costs as a function of vehicle miles traveled, plant capacity and years of operation, corn and soybean production, and soil and environmental conditions.