Iowa Highway Safety Program, Iowa Department of Public Safety, 2002

Annual Highway Safety Report for Iowa Department of Public Safety.

Annual Report of Highway Division, Highway Research and Development in Iowa, November 2002

Annual report for the Iowa Department of Transportation

Full-Size Off-Highway Vehicle Registration Program, December 30, 2003

Report submitted by the Iowa Department of Natural Resources and the Iowa Department of Transportation to the General Assembly as required by Senate File 458, section 152, passed by the 2003 General Assembly and signed May 30, 2003.

Evaluation of the State Highway System and Road Use Tax Fund (RUTF), 2003

This report was prepared by a committee of city, county and state representatives. The committee met throughout 2002 with the purpose of reviewing and making recommendations to improve the efficiency and operation of Iowa's road and street system. This report is referenced in SF 451 and in Code Section 306.8A.

Annual Report for the Iowa Highway Safety Program, Federal Fiscal Year 2003

Annual Highway Safety Evaluation Report for the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

Annual Report for the Iowa Highway Safety Program, 2000

Annual Highway Safety Evaluation Report for the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

Iowa Highway Safety Plan, 2004

Annual Highway Safety Plan for the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

2005 Highway Accomplishment Program, July 1, 2004 to June 30, 2005

Future plans for funding for Iowa Department of Transportation Report.

Annual Report of Highway Division Highway Research and Development in Iowa, 2004

Annual report for Iowa Department of Transportation

2006 Highway Program, July 1, 2005 to June 30, 2006

Future plans for funding for Iowa Department of Transportation Report.

Synthesis of Best Practice for Increasing Protection and Visibility of Highway Maintenance Vehicles, CTRE Final Report Iowa DOT Project TR-475, August 2002

The purpose of this research project is to study current practices in enhancing visibility and protection of highway maintenance vehicles involved in moving operations such as snow removal and shoulder operations, crack sealing, and pothole patching. The results will enable the maintenance staff to adequately assess the applicability and impact of each strategy to their use and budget. The report’s literature review chapter examines the use of maintenance vehicle warning lights, retroreflective tapes, shadow vehicles and truck-mounted attenuators, and advanced vehicle control systems, as well as other practices to improve visibility for both snowplow operators and vehicles. The chapter concludes that the Manual on Uniform Traffic Control Devices does not specify what color or kind of warning lights to use. Thus, a wide variety of lights are being used on maintenance vehicles. The study of the relevant literatures also suggests that there are no clear guidelines for moving work zones at this time. Two types of surveys were conducted to determine current practices to improve visibility and safety in moving work zones across the country and in the state of Iowa. In the first survey of state departments of transportation, most indicated using amber warning lights on their maintenance vehicles. Almost all the responding states indicated using some form of reflective material on their vehicles to make them more visible. Most participating states indicated that the color of their vehicles is orange. Most states indicated using more warning lights on snow removal vehicles than their other maintenance vehicles. All responding state agencies indicated using shadow vehicles and/or truck-mounted attenuators during their moving operations. In the second survey of Iowa counties, most indicated using very similar traffic control and warning devices during their granular road maintenance and snow removal operations. Mounting warning signs and rotating or strobe lights on the rear of maintenance vehicles is common for Iowa counties. The most common warning devices used during the counties’ snow removal operations are reflective tapes, warning flags, strobe lights, and auxiliary headlamps.

Determination and Evaluation of Alternative Methods for Managing and Controlling Highway-Related Dust Phase II—Demonstration Project, June 2005

The State of Iowa currently has approximately 69,000 miles of unpaved secondary roads. Due to the low traffic count on these unpaved o nts as ng e two dust ed d roads, paving with asphalt or Portland cement concrete is not economical. Therefore to reduce dust production, the use of dust suppressants has been utilized for decades. This study was conducted to evaluate the effectiveness of several widely used dust suppressants through quantitative field testing on two of Iowa’s most widely used secondary road surface treatments: crushed limestone rock and alluvial sand/gravel. These commercially available dust suppressants included: lignin sulfonate, calcium chloride, and soybean oil soapstock. These suppressants were applied to 1000 ft test sections on four unpaved roads in Story County, Iowa. Tduplicate field conditions, the suppressants were applied as a surface spray once in early June and again in late August or early September. The four unpaved roads included two with crushed limestone rock and two with alluvial sand/gravel surface treatmewell as high and low traffic counts. The effectiveness of the dust suppressants was evaluated by comparing the dust produced on treated and untreated test sections. Dust collection was scheduled for 1, 2, 4, 6, and 8 weeks after each application, for a total testiperiod of 16 weeks. Results of a cost analysis between annual dust suppressant application and biennial aggregate replacement indicated that the cost of the dust suppressant, its transportation, and application were relatively high when compared to that of thaggregate types. Therefore, the biennial aggregate replacement is considered more economical than annual dust suppressant application, although the application of annual dust suppressant reduced the cost of road maintenance by 75 %. Results of thecollection indicated that the lignin sulfonate suppressant outperformed calcium chloride and soybean oil soapstock on all four unpavroads, the effect of the suppressants on the alluvial sand/gravel surface treatment was less than that on the crushed limestone rock, the residual effects of all the products seem reasonably well after blading, and the combination of alluvial sand/gravel surface treatment anhigh traffic count caused dust reduction to decrease dramatically.

Annual Report of Highway Division Highway Research and Development in Iowa, 2005

Annual report for Iowa Department of Transportation

Annual Report of Highway Division Highway Research and Development in Iowa for the Fiscal Year ending June 30, 2005

The Highway Division of the Iowa Department of Transportation engages in research and development for two reasons: first, to find workable solutions to the many problems that require more than ordinary, routine investigation; second, to identify and implement improved engineering and management practices. This report, entitled Highway Division Highway Research and Development in Iowa, is submitted in compliance with Sections 310.36 and 312.3A, Code of Iowa, which direct the submission of a report of the Secondary Road Research Fund and the Street Research Fund respectively. It is a report of the status of research and development projects, which were in progress on June 30, 2005; it is also a report on projects completed during the fiscal year beginning July 1, 2004, and ending June 30, 2005. Detailed information on each of the research and development projects mentioned in this report is available in the Research and Technology Bureau in the Highway Division of the Iowa Department of Transportation.

Ultra-Thin Portland Cement Concrete Overlay Extended Evaluation, January 2005

In this day of the mature highway systems, a new set of problems is facing the highway engineer. The existing infrastructure has aged to or past the design life of the original pavement design. In many cases, increased commercial traffic is creating the need for additional load carrying capacity, causing state highway engineers to consider new alternatives for rehabilitation of existing surfaces. Alternative surface materials, thicknesses, and methods of installation must be identified to meet the needs of individual pavements and budgets. With overlays being one of the most frequently used rehabilitation alternatives, it is important to learn more about the limitations and potential performance of thin bonded portland cement overlays and subsequent rehabilitation. The Iowa ultra-thin project demonstrated the application of thin portland cement concrete overlays as a rehabilitation technique. It combined the variables of base preparation, overlay thickness, slab size, and fiber enhancement into a series of test sections over a 7.2-mile length. This report identifies the performance of the overlays in terms of deflection reduction, reduced cracking, and improved bonding between the portland cement concrete (PCC) and asphalt cement concrete (ACC) base layers. The original research project was designed to evaluate the variables over a 5-year period of time. A second project provided the opportunity to test overlay rehabilitation techniques and continue measurement of the original overlay performance for 5 additional years. All performance indicators identified exceptional performance over the 10-year evaluation period for each of the variable combinations considered. The report summarizes the research methods, results, and identifies future research ideas to aid the pavement overlay designer in the successful implementation of ultra-thin portland cement concrete overlays as an lternative pavement rehabilitation technique.