Global Prospects for Dairy in Argentina and Chile: Evidence from Field Visits and Model Simulations, August 2006

We assess the international competitiveness of the dairy industries in Argentina and Chile, combining recent market intelligence gathered from field visits with quantitative simulations of global policy reform scenarios. Both countries exhibit strong potential for export growth but face significant internal and external barriers to expanding their dairy industries. Global policy reforms would resolve some of the international obstacles to their expansion. Argentina has great potential, but it is handicapped by its current macroeconomic policies, trade policy distortions, and the uncertainty associated with policy implementation. Chile is more limited in terms of natural capacity for expansion, but it has a positive trade and investment environment.

Calibration of Highway Safety Manual Work Zone Crash Modification Factors, TPF-5(081), 2014

The Highway Safety Manual is the national safety manual that provides quantitative methods for analyzing highway safety. The HSM presents crash modification factors related to work zone characteristics such as work zone duration and length. These crash modification factors were based on high-impact work zones in California. Therefore there was a need to use work zone and safety data from the Midwest to calibrate these crash modification factors for use in the Midwest. Almost 11,000 Missouri freeway work zones were analyzed to derive a representative and stratified sample of 162 work zones. The 162 work zones was more than four times the number of work zones used in the HSM. This dataset was used for modeling and testing crash modification factors applicable to the Midwest. The dataset contained work zones ranging from 0.76 mile to 9.24 miles and with durations from 16 days to 590 days. A combined fatal/injury/non-injury model produced a R2 fit of 0.9079 and a prediction slope of 0.963. The resulting crash modification factors of 1.01 for duration and 0.58 for length were smaller than the values in the HSM. Two practical application examples illustrate the use of the crash modification factors for comparing alternate work zone setups.

On the Segregation of Genetically Modified, Conventional, and Organic Products in European Agriculture: A Multi-market Equilibrium Analysis, October 2005

Evaluating the possible benefits of the introduction of genetically modified (GM) crops must address the issue of consumer resistance as well as the complex regulation that has ensued. In the European Union (EU) this regulation envisions the “co-existence” of GM food with conventional and quality-enhanced products, mandates the labelling and traceability of GM products, and allows only a stringent adventitious presence of GM content in other products. All these elements are brought together within a partial equilibrium model of the EU agricultural food sector. The model comprises conventional, GM and organic food. Demand is modelled in a novel fashion, whereby organic and conventional products are treated as horizontally differentiated but GM products are vertically differentiated (weakly inferior) relative to conventional ones. Supply accounts explicitly for the land constraint at the sector level and for the need for additional resources to produce organic food. Model calibration and simulation allow insights into the qualitative and quantitative effects of the large-scale introduction of GM products in the EU market. We find that the introduction of GM food reduces overall EU welfare, mostly because of the associated need for costly segregation of non-GM products, but the producers of quality-enhanced products actually benefit.

Hydrologic Simulations of the Maquoketa River Watershed Using SWAT Working Paper 09-WP 49,June 2009

This paper describes the application of the Soil and Water Assessment Tool (SWAT) model to the Maquoketa River watershed, located in northeast Iowa. The inputs to the model were obtained from the Environmental Protection Agency’s geographic information/database system called Better Assessment Science Integrating Point and Nonpoint Sources (BASINS). Climatic data from six weather stations located in and around the watershed, and measured streamflow data from a U.S. Geological Survey gage station at the watershed outlet were used in the sensitivity analysis of SWAT model parameters as well as its calibration and validation for watershed hydrology and streamflow. A sensitivity analysis was performed using an influence coefficient method to evaluate surface runoff and base flow variations in response to changes in model input hydrologic parameters. The curve number, evaporation compensation factor, and soil available water capacity were found to be the most sensitive parameters among eight selected parameters when applying SWAT to the Maquoketa River watershed. Model calibration, facilitated by the sensitivity analysis, was performed for the period 1988 through 1993, and validation was performed for 1982 through 1987. The model performance was evaluated by well-established statistical methods and was found to explain at least 86% and 69% of the variability in the measured stream flow data for the calibration and validation periods, respectively. This initial hydrologic modeling analysis will facilitate future applications of SWAT to the Maquoketa River watershed for various watershed analysis, including water quality.

U.S. Universities’ Net Returns from Patenting and Licensing: A Quantile Regression Analysis, September 2006

In line with the rights and incentives provided by the Bayh-Dole Act of 1980, U.S. universities have increased their involvement in patenting and licensing activities through their own technology transfer offices. Only a few U.S. universities are obtaining large returns, however, whereas others are continuing with these activities despite negligible or negative returns. We assess the U.S. universities’ potential to generate returns from licensing activities by modeling and estimating quantiles of the distribution of net licensing returns conditional on some of their structural characteristics. We find limited prospects for public universities without a medical school everywhere in their distribution. Other groups of universities (private, and public with a medical school) can expect significant but still fairly modest returns only beyond the 0.9th quantile. These findings call into question the appropriateness of the revenue-generating motive for the aggressive rate of patenting and licensing by U.S. universities.

Use of Railroad Flat Cars for Low-Volume Road Bridges, August 1999

In an attempt to solve the bridge problem faced by many county engineers, this investigation focused on a low cost bridge alternative that consists of using railroad flatcars (RRFC) as the bridge superstructure. The intent of this study was to determine whether these types of bridges are structurally adequate and potentially feasible for use on low volume roads. A questionnaire was sent to the Bridge Committee members of the American Association of State Highway and Transportation Officials (AASHTO) to determine their use of RRFC bridges and to assess the pros and cons of these bridges based on others’ experiences. It was found that these types of bridges are widely used in many states with large rural populations and they are reported to be a viable bridge alternative due to their low cost, quick and easy installation, and low maintenance. A main focus of this investigation was to study an existing RRFC bridge that is located in Tama County, IA. This bridge was analyzed using computer modeling and field load testing. The dimensions of the major structural members of the flatcars in this bridge were measured and their properties calculated and used in an analytical grillage model. The analytical results were compared with those obtained in the field tests, which involved instrumenting the bridge and loading it with a fully loaded rear tandem-axle truck. Both sets of data (experimental and theoretical) show that the Tama County Bridge (TCB) experienced very low strains and deflections when loaded and the RRFCs appeared to be structurally adequate to serve as a bridge superstructure. A calculated load rating of the TCB agrees with this conclusion. Because many different types of flatcars exist, other flatcars were modeled and analyzed. It was very difficult to obtain the structural plans of RRFCs; thus, only two additional flatcars were analyzed. The results of these analyses also yielded very low strains and displacements. Taking into account the experiences of other states, the inspection of several RRFC bridges in Oklahoma, the field test and computer analysis of the TCB, and the computer analysis of two additional flatcars, RRFC bridges appear to provide a safe and feasible bridge alternative for low volume roads.

Pile Design and Tests for Integral Abutment Bridges, HR-273, 1987

Expansion joints increase both the initial cost and the maintenance cost of bridges. Integral abutment bridges provide an attractive design alternative because expansion joints are eliminated from the bridge itself. However, the piles in these bridges are subjected to horizontal movement as the bridge expands and contracts during temperature changes. The objective of this research was to develop a method of designing piles for these conditions. Separate field tests simulating a pile and a bridge girder were conducted for three loading cases: (1) vertical load only, (2) horizontal displacement of pile head only, and (3) combined horizontal displacement of pile head with subsequent vertical load. Both tests (1) and (3) reached the same ultimate vertical load, that is, the horizontal displacement had no effect on the vertical load capacity. Several model tests were conducted in sand with a scale factor of about 1:10. Experimental results from both the field and model tests were used to develop the vertical and horizontal load-displacement properties of the soil. These properties were input into the finite element computer program Integral Abutment Bridge Two-Dimensional (IAB2D), which was developed under a previous research contract. Experimental and analytical results compared well for the test cases. Two alternative design methods, both based upon the American Association of State Highway and Transportation Officials (AASHTO) Specification, were developed. Alternative One is quite conservative relative to IAB2D results and does not permit plastic redistribution of forces. Alternative Two is also conservative when compared to IAB2D, but plastic redistribution is permitted. To use Alternative Two, the pile cross section must have sufficient inelastic rotation capacity before local buckling occurs. A design example for a friction pile and an end-bearing pile illustrates both alternatives.

Total Cost of Transportation Analysis of Road and Highway Issues, HR-388, 2002

In the administration, planning, design, and maintenance of road systems, transportation professionals often need to choose between alternatives, justify decisions, evaluate tradeoffs, determine how much to spend, set priorities, assess how well the network meets traveler needs, and communicate the basis for their actions to others. A variety of technical guidelines, tools, and methods have been developed to help with these activities. Such work aids include design criteria guidelines, design exception analysis methods, needs studies, revenue allocation schemes, regional planning guides, designation of minimum standards, sufficiency ratings, management systems, point based systems to determine eligibility for paving, functional classification, and bridge ratings. While such tools play valuable roles, they also manifest a number of deficiencies and are poorly integrated. Design guides tell what solutions MAY be used, they aren't oriented towards helping find which one SHOULD be used. Design exception methods help justify deviation from design guide requirements but omit consideration of important factors. Resource distribution is too often based on dividing up what's available rather than helping determine how much should be spent. Point systems serve well as procedural tools but are employed primarily to justify decisions that have already been made. In addition, the tools aren't very scalable: a system level method of analysis seldom works at the project level and vice versa. In conjunction with the issues cited above, the operation and financing of the road and highway system is often the subject of criticisms that raise fundamental questions: What is the best way to determine how much money should be spent on a city or a county's road network? Is the size and quality of the rural road system appropriate? Is too much or too little money spent on road work? What parts of the system should be upgraded and in what sequence? Do truckers receive a hidden subsidy from other motorists? Do transportation professions evaluate road situations from too narrow of a perspective? In considering the issues and questions the author concluded that it would be of value if one could identify and develop a new method that would overcome the shortcomings of existing methods, be scalable, be capable of being understood by the general public, and utilize a broad viewpoint. After trying out a number of concepts, it appeared that a good approach would be to view the road network as a sub-component of a much larger system that also includes vehicles, people, goods-in-transit, and all the ancillary items needed to make the system function. Highway investment decisions could then be made on the basis of how they affect the total cost of operating the total system. A concept, named the "Total Cost of Transportation" method, was then developed and tested. The concept rests on four key principles: 1) that roads are but one sub-system of a much larger 'Road Based Transportation System', 2) that the size and activity level of the overall system are determined by market forces, 3) that the sum of everything expended, consumed, given up, or permanently reserved in building the system and generating the activity that results from the market forces represents the total cost of transportation, and 4) that the economic purpose of making road improvements is to minimize that total cost. To test the practical value of the theory, a special database and spreadsheet model of Iowa's county road network was developed. This involved creating a physical model to represent the size, characteristics, activity levels, and the rates at which the activities take place, developing a companion economic cost model, then using the two in tandem to explore a variety of issues. Ultimately, the theory and model proved capable of being used in full system, partial system, single segment, project, and general design guide levels of analysis. The method appeared to be capable of remedying many of the existing work method defects and to answer society's transportation questions from a new perspective.