Concept Highway Maintenance Vehicle, Final Report, Phase Two, 1998

This report documents Phase II activities of a potentially four-phase project. The goal of the project is to study the feasibility of using advanced technologies from other industries to improve the efficiency and safety of winter highway maintenance vehicle operations. State departments of transportation from Iowa, Minnesota, and Michigan initially formed the study consortium, and several private vendors have become project partners. The Center for Transportation Research and Education (CTRE) at Iowa State University is managing project tasks

Statistical Analysis of Highway Needs Condition Data: Manual vs. Automated, TR-494

This project examines similarities and differences between the automated condition data collected on and off county paved roads and the manual condition data collected by Iowa Department of Transportation (DOT) staff in 2000 and 2001. Also, the researchers will provide staff support to the advisory committee in exploring other options to the highway need process. The results show that the automated condition data can be used in a converted highway needs process with no major differences between the two methods. Even though the foundation rating difference was significant, the foundation rating weighting factor in HWYNEEDS is minimal and should not have a major impact. In terms of RUTF formula based distribution, the results clearly show the superiority of the condition-based analysis compared to the non-condition based. That correlation can be further enhanced by adding more distress variables to the analysis.

Quantifying Uncertainty in Real Time Performance Measurement for Highway Winter Maintenance Operations – Phase 2, RB03-013, 2014

Winter weather in Iowa is often unpredictable and can have an adverse impact on traffic flow. The Iowa Department of Transportation (Iowa DOT) attempts to lessen the impact of winter weather events on traffic speeds with various proactive maintenance operations. In order to assess the performance of these maintenance operations, it would be beneficial to develop a model for expected speed reduction based on weather variables and normal maintenance schedules. Such a model would allow the Iowa DOT to identify situations in which speed reductions were much greater than or less than would be expected for a given set of storm conditions, and make modifications to improve efficiency and effectiveness. The objective of this work was to predict speed changes relative to baseline speed under normal conditions, based on nominal maintenance schedules and winter weather covariates (snow type, temperature, and wind speed), as measured by roadside weather stations. This allows for an assessment of the impact of winter weather covariates on traffic speed changes, and estimation of the effect of regular maintenance passes. The researchers chose events from Adair County, Iowa and fit a linear model incorporating the covariates mentioned previously. A Bayesian analysis was conducted to estimate the values of the parameters of this model. Specifically, the analysis produces a distribution for the parameter value that represents the impact of maintenance on traffic speeds. The effect of maintenance is not a constant, but rather a value that the researchers have some uncertainty about and this distribution represents what they know about the effects of maintenance. Similarly, examinations of the distributions for the effects of winter weather covariates are possible. Plots of observed and expected traffic speed changes allow a visual assessment of the model fit. Future work involves expanding this model to incorporate many events at multiple locations. This would allow for assessment of the impact of winter weather maintenance across various situations, and eventually identify locations and times in which maintenance could be improved.

FY2014 Highway Construction Program Expenditures/Obligations

This report describes the highway construction program, actual expenditures of the program and contractual obligations of the program for FY 2014.

Dedicated to Better and Safer Highways, Iowa State Highway Commission, July 1973

The planning, construction and maintenance of its highways is the state's second highest business, next only to education. Of the nearly 113,090 miles of roads and streets in Iowa, the 10,271 miles in the Interstate and primary system are the direct responsibility of the Highway Commission.From its central headquarters in Ames, the Commission coordinates its statewide activities through facilities located in each of the 99 counties. These include six district offices, 47 resident offices and 165 maintenance garages.

Utility accommodation policy of the Iowa State Highway Commission, 1970

This policy covers initial placement, adjustment, relocation and replacement of utility facilities in, on, above or below all highway right of way over which the Iowa State Highway Commission exercises control of access. It embodies the basic specifications and standards needed, to insure the safety of the highway user and the integrity of the highway.

Utility accommodation policy of the Iowa State Highway Commission, 1973

This policy covers initial placement, adjustment, relocation and replacement of utility facilities in, on, above or below all highway right of way over which the Iowa State Highway Commission exercises control of access. It embodies the basic specifications and standards needed, to insure the safety of the highway user and the integrity of the highway. (1973 revision to 1970 policy.)

Policy for Accommodating Utilities on State Highway Rights-of-Way, 1985

This policy covers initial placement, adjustment, relocation and replacement of utility facilities in, on, above or below all highway right of way over which the Iowa Department of Transportation exercises control of access. It embodies the basic specifications and standards needed, to insure the safety of the highway user and the integrity of the highway. (1985 revision to 1973 policy.)

Policy of the Iowa Department of Transportation Highway Division For Accommodating Utilities on Primary Road System, 1990

This policy covers initial placement, adjustment, relocation and replacement of utility facilities in, on, above or below all highway right of way over which the Iowa Department of Transportation exercises control of access. It embodies the basic specifications and standards needed, to insure the safety of the highway user and the integrity of the highway. (1990 revision to 1985 policy.)

Policy of the Iowa Department of Transportation Highway Division For Accommodating Utilities on the Primary Road System, 1992

This chapter covers initial placement, adjustment, improvement, relocation, replacement and maintenance of utility facilities in, on, above or below the right-of-way over of primary highways, including attachments to primary highway structures. It embodies the basic specifications and standards needed, to ensure the safety of the highway user and the integrity of the highway. (1992 revision to 1990 policy.)

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.

Iowa Highway Research and Development Activities FY2014

This report, entitled Iowa Highway Research and Development Activities FY2014 is submitted in compliance with Iowa Code sections 310.36 and 312.3A, 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 in process on June 20, 2014. It is also a report on projects completed during the fiscal year beginning July 1, 2013 and ending June 30, 2014. Detailed information on each of the research and development projects mentioned in this report is available from the office of Research and Analytics, Performance and Technology Division, Iowa Department of Transportation. All approved reports are also online for viewing at: http://www.iowadot.gov/research/pdf/IHRBAnnualReport.pdf.

Highway "Firsts" - State of Iowa, 1971

Brief summaries of achievement and important events of the Iowa State Highway Commission and transportation engineering in Iowa, between 1904 and 1971.

Making a Modern Highway: Transformation of Iowa Roadways in the Mid-Twentieth Century, 2014

The booklet tells the history of the construction of the Iowa Highway 376 Bridge within the context of significant modernization and expansion of the highway system in Iowa in the 1950s. Curvy, narrow highways were widened and straightened and narrow iron truss bridges were replaced with more modern concrete and steel structures, changing the landscape of rural Iowa. Bridge engineer Herbert A Arthur, who designed the Iowa Highway 376 Bridge, was a prolific bridge engineer in the 1950s. This booklet serves to inform the public of this significant aspect of Iowa transportation history.

Development of Railroad Highway Grade Crossing Consolidation Rating Formula, 2015

The goal of this project was to provide an objective methodology to support public agencies and railroads in making decisions related to consolidation of at-grade rail-highway crossings. The project team developed a weighted-index method and accompanying Microsoft Excel spreadsheet based tool to help evaluate and prioritize all public highway-rail grade crossings systematically from a possible consolidation impact perspective. Factors identified by stakeholders as critical were traffic volume, heavy-truck traffic volume, proximity to emergency medical services, proximity to schools, road system, and out-of-distance travel. Given the inherent differences between urban and rural locations, factors were considered, and weighted, differently, based on crossing location. Application of a weighted-index method allowed for all factors of interest to be included and for these factors to be ranked independently, as well as weighted according to stakeholder priorities, to create a single index. If priorities change, this approach also allows for factors and weights to be adjusted. The prioritization generated by this approach may be used to convey the need and opportunity for crossing consolidation to decision makers and stakeholders. It may also be used to quickly investigate the feasibility of a possible consolidation. Independently computed crossing risk and relative impact of consolidation may be integrated and compared to develop the most appropriate treatment strategies or alternatives for a highway-rail grade crossing. A crossing with limited- or low-consolidation impact but a high safety risk may be a prime candidate for consolidation. Similarly, a crossing with potentially high-consolidation impact as well as high risk may be an excellent candidate for crossing improvements or grade separation. The results of the highway-rail grade crossing prioritization represent a consistent and quantitative, yet preliminary, assessment. The results may serve as the foundation for more rigorous or detailed analysis and feasibility studies. Other pertinent site-specific factors, such as safety, maintenance costs, economic impacts, and location-specific access and characteristics should be considered.