The Regulatory Choice between a Label and a Minimum-Quality Standard, 2005

This paper revisits the issue of the regulatory choice between a mandatory label and a minimum-quality standard. When the cost of regulation is relatively low, we show that the socially optimal choice depends on the producers’ cost structure for complying with regulation and improving quality. Under a marginal cost for improving quality, the mandatory labeling is sufficient for reaching the socially optimal level of quality. Under a fixed cost for improving quality, we show that each instrument or the combination of both instruments may emerge at the equilibrium.

The Minimum Safety Standard, Consumers’ Information, and Competition, February 2007

This paper explores the effects of a standard influencing care choice. Firm(s) may increase the probability of offering safe products by incurring a cost. Under duopoly, they compete either in prices or in quantities. Under perfect information about safety for consumers, the selected standard that corrects a safety underinvestment is always compatible with competition. Safety over investment only emerges under competition in quantities and relatively low values of the cost. Under imperfect information about safety for consumers, the standard leads to a monopoly situation. However, for relatively large values of the cost, a standard cannot impede the market failure coming from the lack of information.

Load Ratings for Standard Bridges, HR-239 Phase IV, 2008

In this report, sixteen secondary and primary bridge standards for two types of bridges are rated for AASHTO HS20-44 vehicle configuration utilizing Load Factor methodology. The ratings apply only to those bridges which: (1) are built according to the applicable bridge standard plans, (2) have no structural deterioration or damage, and (3) have no added wearing surface in excess of one-half inch integral wearing surface.

Load Ratings for Standard Bridges, HR-239 Phase III, 1998

In this report, 25 secondary bridge standards for three types of bridges are rated for the AASHTO HS20-44 vehicle configuration and five typical Iowa legal vehicles. The ratings apply only to those bridges which: (1) are built according to the applicable bridge standard plans, (2) have no structural deterioration or damage, and (3) have no added wearing surface in excess of 0.5-in. (1.27-cm) integral wearing surface. Appendix A contains the results of the original October 1982 report on load ratings for standard bridges.

Load Ratings for Standard Bridges, HR-239, 1982

The load ratings for these Standard bridges were calculated in compliance with the 1978 AASHTO Manual for Maintenance Inspection of Bridges, using the appropriate allowable stresses for the materials specified by the Standard plans. Distribution of loads is in compliance with the Manual unless otherwise noted. Except for truss spans, all bridges with roadway widths of 18 ft. or less were rated for one lane of traffic. All 18 ft. roadway truss bridges were rated for both one and two lanes of traffic. All bridges with roadway widths exceeding 18 ft. were rated for two lanes of traffic. If the posting rating for two lane bridges was less than legal, then the bridges were rated for traffic restricted to one lane, or to one lane centered in the roadway, as noted on the summary sheet. The ratings are applicable to bridges built in accordance with the standard plans and which exhibit no significant deterioration or damage to the structural members, and which have no added wearing surface material in excess of that noted on the summary sheets and used in the calculations. The inventory and operating ratings were based upon the standard AASHTO HS20-44 loading. The legal load ratings were based upon the three typical Iowa legal vehicles shown on page 5. The legal load ratings were based upon the maximum allowable Operating Rating stresses specified in the Manual. Refer to notations on the summary sheets for additional qualifications on the load ratings for specific standard bridge series. Load ratings for standard bridges with wood floors must be based upon existing conditions of attachment of the wood flooring to the top flanges of longitudinal steel stringers. The ratings must be reevaluated if the existing lateral support conditions are not in accordance with conditions used for the rating and noted on the summary sheets. Details of most of the standard bridges are included in the three books of "Iowa State Highway Commission, Bridge Standards," issued in June, 1972. Copies of plans for those standard bridges that were rated, and that are not included in the original books of standard plans, are being furnished under separate cover with these rating summaries.

Standard Specifications for Highway and Bridge Construction, 2012

When referenced, the 2012 edition of the Iowa Department of Transportation’s (Iowa DOT) Standard Specifications for Highway and Bridge Construction shall be used for contract work awarded by the Iowa DOT. They may also be incorporated by reference in other contract work on secondary, urban, local systems, or other contract work in which the Iowa DOT has an interest. As modified by the General Supplemental Specifications, these Standard Specifications represent the minimum requirements and may be modified by Supplemental Specifications, Developmental Specifications, and Special Provisions on specific contracts. These Standard Specifications have been written so the Contractor’s responsibilities are indicated by plain language using the Imperative Mood and Active Voice form. Sentences are of the form: Construct isolation joints at all points where driveways meet other walks, curbs, or fixtures in the surface. Ensure finished members are true to detailed dimensions and free from twists, bends, open joints, or other defects resulting from faulty fabrication or defective work. Personnel preparing the JMF shall be Iowa DOT certified in bituminous mix design. The Contracting Authority’s responsibilities are (with some exceptions) indicated by the use of the modal verb “will”. Sentences are of the form: The Engineer will obtain and test density samples for each lot according to Materials I.M. 204. Payment will be the contract unit price for Fabric Reinforcement per square yard (square meter). These standard specifications contain dual units of measure: the United States Standard measure (English units) and the International System of Units (SI or “metric” units). The English units are expressed first then followed by the metric units in parentheses. The measurements expressed in the two systems are not necessarily equal. In some cases the measurements in metric units is a “hard” conversion of the English measurement; i.e. the metric unit has been approximated with a rounded, rationalized metric measurement that is easy to work with and remember. The proposal form will identify whether the work was designed and shall be constructed in English or metric units.

Concrete Pavement Mixture Design and Analysis (MDA): Evaluation of the Fresh and Hardened Properties of Concrete Mixtures Containing Permeability-Reducing Admixtures to Develop Standard Test Protocol, 2014

Concrete durability may be considered as the ability to maintain serviceability over the design life without significant deterioration, and is generally a direct function of the mixture permeability. Therefore, reducing permeability will improve the potential durability of a given mixture and, in turn, improve the serviceability and longevity of the structure. Given the importance of this property, engineers often look for methods that can decrease permeability. One approach is to add chemical compounds known as integral waterproofing admixtures or permeability-reducing admixtures, which help fill and block capillary pores in the paste. Currently, there are no standard approaches to evaluate the effectiveness of permeability-reducing admixtures or to compare different products in the US. A review of manufacturers’ data sheets shows that a wide range of test methods have been used, and rarely are the same tests used on more than one product. This study investigated the fresh and hardened properties of mixtures containing commercially available hydrophilic and hydrophobic types of permeability-reducing admixtures. The aim was to develop a standard test protocol that would help owners, engineers, and specifiers compare different products and to evaluate their effects on concrete mixtures that may be exposed to hydrostatic or non-hydrostatic pressure. In this experimental program, 11 concrete mixtures were prepared with a fixed water-to-cement ratio and cement content. One plain mixture was prepared as a reference, 5 mixtures were prepared using the recommended dosage of the different permeability-reducing admixtures, and 5 mixtures were prepared using double the recommended dosage. Slump, air content, setting time, compressive and flexural strength, shrinkage, and durability indicating tests including electrical resistivity, rapid chloride penetration, air permeability, permeable voids, and sorptivity tests were conducted at various ages. The data are presented and recommendations for a testing protocol are provided.

Reuse of Lime Sludge from Water Softening and Coal Combustion Byproducts, TR-459, 2004

Disposal of lime sludge remains a major challenge to cities in the Midwest. Disposal of lime sludge from water softening adds about 7-10% to the cost of water treatment. Having effective and safe options is essential for future compliance with the regulations of the State of Iowa and within budget restrictions. Dewatering and drying are essential to all reuse applications as this affects transportation costs and utility. Feasibility tests were conducted on some promising applications like SOx control in power generation facilities that burn coal, replacement of limestone as an ingredient in portland cement production, dust control on gravel roads, neutralization of industrial wastewater pH, and combination with fly ash or cement in construction fill applications. A detailed report and analysis of the construction fills application is presented in the second half of the report. A brief discussion of the results directly follows.

Biological Sampling and Physical Habitat Assessment Standard Operating Procedure for Iowa Wadeable Streams and Rivers, July 24, 2015

The Iowa Department of Natural Resources uses benthic macroinvertebrate and fish sampling data to assess stream biological condition and the support status of designated aquatic life uses (Wilton 2004; IDNR 2013). Stream physical habitat data assist with the interpretation of biological sampling results by quantifying important physical characteristics that influence a stream’s ability to support a healthy aquatic community (Heitke et al., 2006; Rowe et al. 2009; Sindt et al., 2012). This document describes aquatic community sampling and physical habitat assessment procedures currently followed in the Iowa stream biological assessment program. Standardized biological sampling and physical habitat assessment procedures were first established following a pilot sampling study in 1994 (IDNR 1994a, 1994b). The procedure documents were last updated in 2001 (IDNR 2001a; 2001b). The biological sampling and physical habitat assessment procedures described below are evaluated on a continual basis. Revision of this working document will occur periodically to reflect additional changes.

Vertical Clearance Restrictions on Primary Roads and Primary Road Extensions: Standard U.S. Measurements [Vertical Clearance Log], May 1, 2015

The Vertical Clearance Log is prepared for the purpose of providing vertical clearance restrictions by route on the primary road system. This report is used by the Iowa Department of Transportation’s Motor Carrier Services to route oversize vehicles around structures with vertical restrictions too low for the cargo height. The source of the data is the Geographic Information Management System (GIMS) that is managed by the Office of Research & Analytics in the Performance & Technology Division. The data is collected by inspection crews and through the use of LiDAR technology to reflect changes to structures on the primary road system. This log is produced annually.