Traffic map, Iowa,1984.

Traffic volumes represented on this map are average volumes between major traffic generators: highway junctions, cities, recreational areas or high volume secondary roads.

Road Use Tax Fund Efficiency Report, June 30, 2013

Senate File 2314, 84th General Assembly, states the Iowa Department of Transportation shall submit quarterly reports regarding the implementation of efficiency measures identified in the "Road Use Tax Fund Efficiency Report," January 2012. This report shall provide details of activities undertaken in the previous quarter relating to one-time and long-term program efficiencies and partnership efficiencies. Issues covered include savings realized from the implementation of particular efficiency measures; updates concerning measures that have not been implemented; efforts involving cities, counties, other jurisdictions, or stakeholder interest groups; any new efficiency measures identified or undertaken; and identification of any legislative action that may be required to achieve efficiencies.

Evaluation of Low Cost Traffic Calming for Rural Communities – Phase II, April 2013

The main goal of the research described in this report was to evaluate countermeasures that agencies can use to reduce speeds as drivers enter rural communities located on high-speed roadways. The objectives of this study were as follows: * Identify and summarize countermeasures used to manage speeds in transition zones * Demonstrate the effectiveness of countermeasures that are practical for high- to low-speed transition zones * Acquire additional information about countermeasures that may show promise but lack sufficient evidence of effectiveness * Develop an application toolbox to assist small communities in selecting appropriate transition zones and effective countermeasures for entrances to small rural communities The team solicited small communities that were interested in participating in the Phase II study and several communities were also recommended. The treatments evaluated were selected by carefully considering traffic-calming treatments that have been used effectively in other countries for small rural communities, as well as the information gained from the first phase of the project. The treatments evaluated are as follows: * Transverse speed bars * Colored entrance treatment * Temporary island * Radar-activated speed limit sign * Speed feedback sign The toolbox publication and four focused tech briefs also cover the results of this work.

Evaluation of In-Use Fuel Economy and On-Board Emissions for Hybrid and Regular CyRide Transit Buses, October 2012

The objective of this project was to evaluate the in-use fuel economy and emission differences between hybrid-electric and conventional transit buses for the Ames, Iowa transit authority, CyRide. These CyRide buses were deployed in the fall of 2010. Fuel economy was compared for the hybrid and control buses. Several older bus types were also available and were included in the analysis. Hybrid buses had the highest fuel economy for all time periods for all bus types. Hybrid buses had a fuel economy that was 11.8 percent higher than control buses overall, 12.2 percent higher than buses with model years 2007 and newer, 23.4 percent higher than model years 2004 through 2006, 10.2 percent higher than model years 1998 through 2003, 38.1 percent higher than model years 1994 through 1997, 36.8 percent higher than model years 1991 through 1993, and 36.8 percent higher for model years pre-1991. On-road emissions were also compared for three of the hybrid buses and two control buses using a portable emissions monitor. On-average, carbon dioxide, carbon monoxide, and hybrid carbon emissions were much higher for the control buses than for the hybrid buses. However, on average nitrogen oxide emissions were higher for the hybrid buses.

Road Safety Audit for IA 28 from the South Corporate Limits of Norwalk in Warren County through the IA 5 Interchange in Polk County, Iowa, November 2012

In response to local concerns, the Iowa Department of Transportation (DOT) requested a road safety audit (RSA) for the IA Highway 28 corridor through the City of Norwalk in Warren County, Iowa, from the south corporate limits of Norwalk through the IA 5 interchange in Polk County, Iowa. The audit included meeting with City staff to discuss concerns, review crash history and operational issues, observe the route under daylight and nighttime conditions, and analyze available data. This report outlines the findings and recommendations of the audit team for addressing the safety concerns and operational matters along this corridor.

Final Report on the Portable Computerized Assessments of Sleepy Drivers in Operational Environments, June 29, 2011

Excessive daytime sleepiness underpins a large number of the reported motor vehicle crashes. Fair and accurate field measures are needed to identify at-risk drivers who have been identified as potentially driving in a sleep deprived state on the basis of erratic driving behavior. The purpose of this research study was to evaluate a set of cognitive tests that can assist Motor Vehicle Enforcement Officers on duty in identifying drivers who may be engaged in sleep impaired driving. Currently no gold standard test exists to judge sleepiness in the field. Previous research has shown that Psychomotor Vigilance Task (PVT) is sensitive to sleep deprivation. The first goal of the current study was to evaluate whether computerized tests of attention and memory, more brief than PVT, would be as sensitive to sleepiness effects. The second goal of the study was to evaluate whether objective and subjective indices of acute and cumulative sleepiness predicted cognitive performance. Findings showed that sleepiness effects were detected in three out of six tasks. Furthermore, PVT was the only task that showed a consistent slowing of both ‘best’, i.e. minimum, and ‘typical’ responses, median RT due to sleepiness. However, PVT failed to show significant associations with objective measures of sleep deprivation (number of hours awake). The findings indicate that sleepiness tests in the field have significant limitations. The findings clearly show that it will not be possible to set absolute performance thresholds to identify sleep-impaired drivers based on cognitive performance on any test. Cooperation with industry to adjust work and rest cycles, and incentives to comply with those regulations will be critical components of a broad policy to prevent sleepy truck drivers from getting on the road.

Modified Sheet Pile Abutments for Low-Volume Road Bridges, January 2012

To date there have been few investigations of the substructures in low-volume road (LVR) bridges. Steel sheet piling has the potential to provide an economical alternative to concrete bridge abutments, but it needs investigation with regard to vertical and lateral load resistance, construction methods, and performance monitoring. The objectives of this project were to develop a design approach for sheet pile bridge abutments for short-span low-volume bridges, formulate an instrumentation and monitoring plan to evaluate performance of sheet pile abutment systems, and understand the cost and construction effort associated with building the sheet pile bridge abutment demonstration project. Three demonstration projects (Boone, Blackhawk, and Tama Counties) were selected for the design, construction, and monitoring of sheet pile abutments bridges. Each site was unique and required site-specific design and instrumentation monitoring. The key findings from this study include the following: (1) sheet pile abutment bridges provide an effective solution for LVR bridges, (2) the measured stresses and deflection were different from the assumed where the differences reflect conservatism in the design and the complex field conditions, and (3) additional research is needed to optimize the design.

Modified Sheet Pile Abutments for Low-Volume Road Bridges: Tech Transfer Summary, January 2012

Iowa has about 22,936 bridges on low-volume roads (LVRs). Based on the National Bridge Inventory data, 22 percent of the LVR bridges in Iowa are structurally deficient, while 5 percent of them are functionally obsolete. The substructure components (abutment and foundation elements) are known to be contributing factors for some of these poor ratings. Steel sheet piling was identified as a possible long-term option for LVR bridge substructures; but, due to lack of experience, Iowa needed investigation with regard to vertical and lateral load resistance, construction methods, design methodology, and load test performance. This project was initiated in January 2007 to investigate use of sheet pile abutments. *************Tech Transfer Summary. For full report see: http://publications.iowa.gov/id/eprint/14832*************

Annual Average Daily Traffic on the Interstate System, 2012

Vehicle Traffic Map produced by the Iowa Department of Transportation.

Vehicle Traffic Map, 2012

Vehicle Traffic Map produced by the Iowa Department of Transportation.

Truck Traffic Map, 2012

Vehicle Traffic Map produced by the Iowa Department of Transportation.

Improving Traffic Safety Culture in Iowa – Phase II, July 2013

Phase II of Improving Traffic Safety Culture in Iowa focuses on producing actions that will improve the traffic safety culture across the state, and involves collaboration among the three large public universities in Iowa: Iowa State University, University of Northern Iowa, and University of Iowa. More specifically, this second phase synthesizes the expert opinions solicited in Phase I with prevailing public views and/or opinions gathered from a follow-up survey on Iowa’s 2000 public opinion survey, which the University of Northern Iowa, Center for Social and Behavioral Research, administered. More recent data on the opinions of Iowans and of people nationally contrasted with past data will help better define the public’s position on top safety culture issues. This, in turn, will provide a better basis for developing actionable, fundable, and ultimately successful strategies that will make a tangible difference in improving traffic safety in Iowa.

Evaluation of Mitigation for Safety Concerns on Low-Volume, Unpaved Rural Roads, 2013.

The Institute for Transportation (InTrans) at Iowa State University completed work on an in-depth study of crash history on lowvolume, rural roads in Iowa in December 2010. Results indicated that unpaved roads with traffic volumes greater than 100 vehicles per day (vpd) exhibit significantly higher crash frequencies, rates, and densities than any other class of low-volume road examined, paved or unpaved. The total mileage for this class of roadway in Iowa is only about 4,400 miles, spread over 99 counties in the state, which is certainly a manageable number of miles for individual rural agencies. The purpose of this study was to identify and examine several unpaved, local road segments with higher than average crash frequencies, select and undertake potentially-beneficial mitigation, and evaluate the results as time allowed. A variety of low-cost options were considered, including engineering improvements, enhanced efforts by law enforcement, and educational initiatives. Using input, active support, and participation from local agencies and state and Federal safety advocates, the study afforded a unique opportunity to examine useful tools for local rural agencies to utilize in addressing safety on this particular type of roadway.

Evaluation of Mitigation for Safety Concerns on Low-Volume, Unpaved Rural Roads: Tech Transfer Summary, 2013.

The Institute for Transportation (InTrans) at Iowa State University completed work on an in-depth study of crash history on lowvolume, rural roads in Iowa in December 2010. Results indicated that unpaved roads with traffic volumes greater than 100 vehicles per day (vpd) exhibit significantly higher crash frequencies, rates, and densities than any other class of low-volume road examined, paved or unpaved. The total mileage for this class of roadway in Iowa is only about 4,400 miles, spread over 99 counties in the state, which is certainly a manageable number of miles for individual rural agencies. The purpose of this study was to identify and examine several unpaved, local road segments with higher than average crash frequencies, select and undertake potentially-beneficial mitigation, and evaluate the results as time allowed. A variety of low-cost options were considered, including engineering improvements, enhanced efforts by law enforcement, and educational initiatives. Using input, active support, and participation from local agencies and state and Federal safety advocates, the study afforded a unique opportunity to examine useful tools for local rural agencies to utilize in addressing safety on this particular type of roadway.