Maximized Utility of the Global Positioning System, HR-316, 1991

This report describes a project begun in January 1989 and completed December 1990, with the primary objective of obtaining sufficiently accurate horizontal and vertical control by using Global Positioning System (GPS) for highway applications. The ISU research group studied the operations of the Ashtech GPS receiver in static, pseudo-static, kinematic, and pseudo-kinematic modes. By using the Electronic Distance Measuring Instrument (EDMI) Calibration Baseline at ISU, the GPS receiver was tested for distance measurement accuracy. It was found that GPS measurements differed from the baseline distance by about 5.3 mm. Four projects were undertaken to further evaluate and improve the horizontal as well as the vertical accuracies of the GPS receiver -- (1) The Campus Project: with all points concentrated within a one-mile radius; (2) The Des Moines Project: a typical DOT project with all the points within a five-mile radius; (3) The Iowa Project: with all points within a 100-mile radius in the state of Iowa; and (4) The Mustang Project: an extension of the Iowa project, including a typical DOT project of about 10 miles within the inner 30 mile radius of the Iowa project.

Socioeconomic Effects of Gambling on Iowans Study Committee, 2004

Overview. The Studies Committee received an in-person progress report from the consultants retained by the Legislature to conduct a study of the socioeconomic effects of gambling on Iowans. Dr. Deepak Chhabra and Dr. Gene Lutz, both of the University of Northern Iowa, presented an update on the conduct of the study. Gambling Study Description. The consultants indicated that the study objectives are to determine the economic impact of gambling at existing Iowa casinos on the local community, the socioeconomic characteristics of gamblers, the social impact of gambling on the local community, and the impact of problem gambling. The consultants stated that the major research methods they would use would be historical data, telephone surveys of local residents, telephone interviews with key personnel, and use of an economic impact model. In conducting the study, the consultants indicated they would examine four study areas within Iowa. Study area I would be all of Iowa, area II would be that area in Iowa within a 50-mile radius of a casino, area III would be counties with a casino, and area IV would be based upon casino employee zip codes. The consultants briefed the Committee on the data collected so far and described current challenges in obtaining data on all casino visitors and from obtaining information from several convention and visitor bureaus and chambers of commerce.

Vibration Study for Consolidation of Portland Cement Concrete, Preprint, MLR-95-4, 1997

The Iowa Department of Transportation has discovered an increase in the occurrence of excessively vibrated portland cement concrete (PCC) pavements. The overconsolidation of PCC pavements has been observed in several projects across the state. Overconsolidation is also believed to be a factor in acceleration of premature deterioration of at least two pavement projects in Iowa. To address the problem, a research project in 1995 documented the vibratory practices of PCC slipform paving in Iowa in order to determine the effect of vibration on consolidation and air content of pavement. Paver speed, vibrator frequency, and air content relative to the location of the vibrator were studied. The study concluded that the Iowa Department of Transportation specification of 5,000 to 8,000 vibrations per minute (vpm) for slipform pavers is effective for normal paver speeds on the three projects that were examined. Excessive vibration was clearly identified on one project where a vibrator frequency of 12,000 vpm was discovered. When the paver speed was reduced to half the normal speed, hard air contents indicate that excessive vibration was beginning to occur in the localized area immediately surrounding the vibrator at a frequency of 8,000 vpm. The study also indicates that the radius of influence of the vibrators is smaller than has been claimed.

Evaluation of Deicing Materials and Corrosion Reducing Treatments for Deicing Salts, TR-471, 2007

Effective winter maintenance makes use of freezing-point-depressant chemicals (also known as ice-control products) to prevent the formation of the bond between snow and ice and the highway pavement. In performing such winter maintenance, the selection of appropriate ice-control products for the bond prevention task involves consideration of a number of factors, as indicated in Nixon and Williams (2001). The factors are in essence performance measurements of the ice-control products, and as such can be easily incorporated into a specification document to allow for selection of the best ice-control products for a given agency to use in its winter maintenance activities. Once performance measures for de-icing or anti-icing chemicals have been specified, this allows the creation of a quality control program for the acceptance of those chemicals. This study presents a series of performance measurement tests for ice-control products, and discusses the role that they can play in such a quality control program. Some tests are simple and rapid enough that they can be performed on every load of icecontrol products received, while for others, a sampling technique must be used. An appropriate sampling technique is presented. Further, each test is categorized as to whether it should be applied to every load of ice-control products or on a sampling basis. The study includes a detailed literature review that considers the performance of ice-control products in three areas: temperature related performance, product consistency, and negative side effects. The negative side effects are further broken down into three areas, namely operational side effects (such as chemical slipperiness), environmental side effects, and infrastructural side effects (such as corrosion of vehicles and damage to concrete). The review indicated that in the area of side effects the field performance of ice-control products is currently so difficult to model in the laboratory that no particular specification tests can be recommended at this time. A study of the impact of ice-control products on concrete was performed by Professor Wang of Iowa State University as a sub-contract to this study, and has been presented to the Iowa Highway Research Board prior to this report.

Evaluation of the SHRP Modified Georgia Digital Faultmeter, MLR-93-01, 1993

The SHRP Modified Georgia Digital Faultmeter was loaned to the Iowa Department of Transportation in January 1993 for evaluation. A study was undertaken comparing the faultmeter to Iowa's current method of fault measurement. The following conclusions were made after comparing the faultmeter to Iowa's gauge: The faultmeter was lighter and easier to maneuver and position. The faultmeter's direct readout was quicker to read. The faultmeter has increased precision. The faultmeter gave consistently lower fault readings than the Iowa gauge.