Performance Measurement for Highway Winter Maintenance Operations, TR-491, 2009

The goal of this research project was to develop a method to measure the performance of a winter maintenance program with respect to the task of providing safety and mobility to the travelling public. Developing these measures required a number of steps, each of which was accomplished. First, the impact of winter weather on safety (crash rates) and mobility (average vehicle speeds were measured by a combination of literature reviews and analysis of Iowa Department of Transportation traffic and Road Weather Information System data. Second, because not all winter storms are the same in their effects on safety and mobility, a method had to be developed to determine how much the various factors that describe a winter storm actually change safety and mobility. As part of this effort a storm severity index was developed, which ranks each winter storm on a scale between 0 (a very benign storm) and 1 (the worst imaginable storm). Additionally a number of methods of modeling the relationships between weather, winter maintenance actions and road surface conditions were developed and tested. The end result of this study was a performance measure based on average vehicle speed. For a given class of road, a maximum expected average speed reduction has been identified. For a given storm, this maximum expected average speed reduction is modified by the storm severity index to give a target average speed reduction. Thus, if for a given road the maximum expected average speed reduction is 20 mph, and the storm severity for a particular storm is 0.6, then the target average speed reduction for that road in that storm is 0.6 x 20 mph or 12 mph. If the average speed on that road during and after the storm is only 12 mph or less than the average speed on that road in good weather conditions, then the winter maintenance performance goal has been met.

Bridge Rail and Approach Railing for Low-Volume Roads in Iowa, TR-592, 2010

Bridge rail and approach guardrails provide safety to drivers by shielding more hazardous objects and redirecting vehicles to the roadway. However, guardrail can increase both the initial cost and maintenance cost of a bridge, while adding another object that may be struck by vehicles. Most existing low volume road (LVR) bridges in the state of Iowa are currently indicated to not possess bridge rail meeting “current acceptable standards”. The primary objective of the research summarized in this report was to provide the nations bridge and approach rail state of practice and perform a state wide crash analysis on bridge rails and approach guardrails on LVR bridges in Iowa. In support of this objective, the criteria and guidelines used by other bridge owners were investigated, non-standard and innovative bridge and approach guardrails for LVR’s were investigated, and descriptive, statistical and economical analyses were performed on a state wide crash analysis. The state wide crash analysis found the overall number of crashes at/on the more than 17,000+ inventoried and non-inventoried LVR bridges in Iowa was fewer than 350 crashes over an eight year period, representing less than 0.1% of the statewide reportable crashes. In other words, LVR bridge crashes are fairly rare events. The majority of these crashes occurred on bridges with a traffic volume less than 100 vpd and width less than 24 ft. Similarly, the majority of the LVR bridges possess similar characteristics. Crash rates were highest for bridges with lower traffic volumes, narrower widths, and negative relative bridge widths (relative bridge width is defined as: bridge width minus roadway width). Crash rate did not appear to be effected by bridge length. Statistical analysis confirmed that the frequency of vehicle crashes was higher on bridges with a lower width compared to the roadway width. The frequency of crashes appeared to not be impacted by weather conditions, but crashes may be over represented at night or in dark conditions. Statistical analysis revealed that crashes that occurred on dark roadways were more likely to result in major injury or fatality. These findings potentially highlight the importance of appropriate delineation and signing. System wide, benefit-cost (B/C) analyses yielded very low B/C ratios for statewide bridge rail improvements. This finding is consistent with the aforementioned recommendation to address specific sites where safety concerns exist.

Low-Cost Rural Surface Alternatives: Demonstration Project, TR-664, 2015

The goals of this project were to implement several stabilization methods for preventing or mitigating freeze-thaw damage to granular surfaced roads and identify the most effective and economical methods for the soil and climate conditions of Iowa. Several methods and technologies identified as potentially suitable for Iowa were selected from an extensive analysis of existing literature provided with Iowa Highway Research Board (IHRB) Project TR-632. Using the selected methods, demonstration sections were constructed in Hamilton County on a heavily traveled two-mile section of granular surfaced road that required frequent maintenance during previous thawing periods. Construction procedures and costs of the demonstration sections were documented, and subsequent maintenance requirements were tabulated through two seasonal freeze-thaw periods. Extensive laboratory and field tests were performed prior to construction, as well as before and after the two seasonal freeze-thaw periods, to monitor the performance of the demonstration sections. A weather station was installed at the project site and temperature sensors were embedded in the subgrade to monitor ground temperatures up to a depth of 5 ft and determine the duration and depths of ground freezing and thawing. An economic analysis was performed using the documented construction and maintenance costs, and the estimated cumulative costs per square yard were projected over a 20-year timeframe to determine break-even periods relative to the cost of continuing current maintenance practices. Overall, the sections with biaxial geogrid or macadam base courses had the best observed freeze-thaw performance in this study. These two stabilization methods have larger initial costs and longer break-even periods than aggregate columns, but counties should also weigh the benefits of improved ride quality and savings that these solutions can provide as excellent foundations for future paving or surface upgrades.

Iowa 58 Viking Road Corridor from U.S. 20 to Greenhill Road in Cedar Falls, Iowa, NHSX-U-58-1(91)--8S-07, 2015

The Proposed Action consists of the improvement of Iowa Highway 58 (IA 58) from U.S. Highway 20 (U.S. 20) north to Greenhill Road in Cedar Falls (Black Hawk County, Iowa). The improvement would include limiting at-grade access to IA 58 by adding one or more interchanges to the corridor which would be located at Viking Road, Greenhill Road, and reconfiguring the U.S. 20 interchange (Figure 1). In order to construct these interchanges and associated ramps, the pavement of IA 58 would be reconstructed. In a couple of locations, the alignment of IA 58 would be shifted.

East 1 St Street Interchange and I-35 Widening, From MP 94.3 to Oralabor Road, Polk County, Iowa, Project # IM-035-4(140)92--13-77, Environmental Assessment and Section 4(f) De Minimis Impact Finding, 2015

From Proposed Action: "The proposed action consists of reconstructing the East 1st Street/I-35 interchange with a Diverging Diamond interchange, widening I-35 from four (4) lanes to six (6) lanes, and widening East 1st Street from four (4) lanes to five (5) lanes from Delaware Avenue to Frisk Drive. The project also proposes to reconstruct the intersections of East 1st Street/Creekview Drive and East 1st Street/Frisk Drive."

Performance Measures for Iowa Transportation Systems, 2006

The purpose of performance measures in planning operations is to identify and track meaningful, quantifiable measures that reflect progress toward the goals of the plan. The Iowa Department of Transportation (DOT) has already adopted performance measures in a number of operational areas, including highway maintenance, highway safety, public transportation, and aeronautics. This report is an initial effort to utilize performance measures for transportation system planning. The selected measures provide a cross-section of system performance indicators across three selected transportation planning goals (safety, efficiency, and quality of life) and five transportation modes (highways/bridges, public transit, railroads, aviation, and pedestrian/bicycle). These performance measures are exploratory in nature, and constitute a first attempt to apply performance measures in the context of a statewide, multimodal transportation plan from the Iowa DOT. As such, the set of performance measures that the Iowa DOT uses for planning will change over time as more is learned about the application of such measures. The performance measures explained in this document were developed through consultation with Iowa DOT modal staff (aviation, railroads, highways, public transportation, and pedestrian/bicycle) and the Office of Traffic and Safety. In addition, faculty and staff at the Iowa State University Center for Transportation Research and Education were consulted about performance measurement and data within their areas of expertise.

Synthesis of Traffic Calming Techniques in Work Zones, 2009

Nationwide, over 1,000 fatalities and 40,000 injuries occur annually in work zones, which include both construction zones and areas where maintenance is performed. The majority (85%) of work zone accidents result from unsafe driver behavior, and vehicle speed is often a factor in work zone crashes. In order to address speed and driver behavior near work zones, roadway agencies have developed different traffic calming measures. The objective of this research is to summarize the effectiveness of different traffic calming treatments for reducing speeds in work zones. This project 1. identified work zone traffic calming treatments for which information has not been well summarized, 2. identified state of the art and new technologies for work zone traffic calming, and 3. synthesized research related to items 1 and 2

Enhancing Motorcycle Conspicuity Awareness in Iowa, 2010

Previous studies in the United States and internationally suggest that low motorcycle conspicuity, or the inability of the motorcyclist to be seen by other road users, is thought to be an important factor associated with risk of motorcycle crashes. However, there has been limited research on motorcycle conspicuity in the United States in the past two decades, while at the same time; there has been a renewed interest from states in increasing motorcycle conspicuity and motorist awareness. As such, this research revisits the motorcycle conspicuity problem by analysis of helmet-use and motorcycle crash data. First, this study reviews previous studies on motorcycle conspicuity with a focus on the effectiveness of proposed measures for enhancing motorcycle conspicuity. The major trends in motorcycle helmet use by time of day and road type for motorcyclists, as indicated from three roadside observational roadside surveys in Iowa, are also discussed. Then, using motorcycle crash data for Iowa from 2001 to 2008, this research compares single-and two-vehicle motorcycle crashes and examines the distribution of conspicuity related factors in light and dark conditions in two-vehicle crashes that could potentially relate to a collision between a motorcycle and another vehicle. The limitations of examining motorcycle conspicuity by analysis of crash data are also discussed. Finally, this report outlines recommendations based on the key findings of the study.

Implementation of the Federal Highway Administration Final Rule on Work Zone Safety and Mobility, 2007

The Federal Highway Administration published the final rule updating 23 CFR 630 Subpart J in September 2004. The revised rule requires agencies using federal funding to address both safety and mobility in planning and construction of roadway improvements. The Iowa Department of Transportation (Iowa DOT) requested the assistance of the Center for Transportation and Research in developing guidance for a policy and procedures to comply with the final rule. This report describes an in-depth examination of current Iowa DOT project development processes for all types of improvements, including maintenance, as well as a detailed characterization of work zone impact considerations throughout project completion. To comply with both the letter and perceived intent of the final rule on safety and mobility, the report features a suggested work zone policy statement and suggested revisions in the Iowa DOT project development processes, including a definition of the key element: significant projects.

Road Use Tax Fund Efficiency Report savings status, December 31, 2015

Senate File 2355, 85th General Assembly, states the Iowa Department of Transportation shall submit annual 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 year relating to one-time and long-term program efficiencies and partnership efficiencies. Issues to be covered in the reports shall include but are not limited to 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 Work Zone Speed Reduction Measures, 2000

The Iowa Department of Transportation (DOT) has made improving work zone (WZ) safety a high priority. Managing vehicle speeds through work zones is perceived to be an important factor in achieving this goal. A number of speed reduction techniques are currently used by transportation agencies throughout the country to control speeds and reduce speed variation at work zones. The purpose of this project is to study these and other applicable work zone speed reduction strategies. Furthermore, this research explores transportation agencies' policies regarding managing speeds in long-term, short-term, and moving work zones. This report consists of three chapters. The first chapter, a literature review, examines the current speed reduction practices at work zones and provides a review of the relevant literature. The speed control strategies reviewed in this chapter range from posting regulatory and advisory speed limit signs to using the latest radar technologies to reduce speeds at work zones. The second chapter includes a short write-up for each identified speed control technique. The write-up includes a description, the results of any field tests, the benefits and the costs of the technology or technique. To learn more about other state policies regarding work zone speed reduction and management, the Center for Transportation Research and Education conducted a survey. The survey consists of six multipart questions. The third chapter provides summaries of the response to each question.

Communicating Highway Safety: What Works, 2002

Few topics in transportation are of greater significance, now and in the future, than making today’s roads safe for those who use them. This study aims to assist the formulation of policy by examining the empirical evidence currently available on the ability of several forms of communication efforts and activities to increase knowledge about and affect attitudes and behavior toward highway safety practices. The objective of this effort is to provide a comparative synthesis of what works and what does not in highway safety campaigns across a large number of topical areas that have a mass media component. This was accomplished by conducting an extensive literature review to determine the current state of knowledge concerning what works and what has significant potential for wide use in future highway safety campaigns. An analytic framework for investigating highway safety campaigns was created. The framework includes (1) the types of media components, (2) the types of collaborations, (3) the context in which the campaign is intended to have impact, (4) the structure or procedural steps into which campaigns are organized, (5) the principles for what works in a campaign, and (6) the desired impact of a campaign on its target audience. The report reveals 25 characteristics of successful communication campaigns, strategies that stand a chance of achieving changes in knowledge, attitude, and behavior. The actual impact of mass communication remains unproven because of a perceived lag in the development of adequate evaluation techniques. Education by itself has not generally resulted in significant changes in the behaviors targeted, but education of the public and advocacy groups has often helped enact necessary legislation, transmit knowledge about the provisions and penalties of laws in ways that increase their deterrent effect, and generate public support for law enforcement programs. Even in such cases, however, when enforcement is inconsistent, public compliance frequently decreases with time. Approaches to traffic safety that emphasize the need for long-term individual- and community-based measures are found to be especially crucial for addressing complex problems like drinking and driving that are determined by a myriad of lifestyle and psychosocial factors.

Corridor Management Pilot Projects, 2004

Managing existing and newly constructed highway corridors has recently become a significant concern in many states, including Iowa. As urban land and land on the urban fringe develops, there is pressure to add features such as commercial driveways, at-grade public road intersections, and traffic signals to arterial highway routes that should primarily serve high-speed traffic. This diminishes the speed and traffic capacity of such roadways and can also cause significant safety issues. if mobility and safety are diminished, the value of the highway investment is diminished. Since a major highway corridor improvement may cost tens of millions of dollars or more, corridor management is as critical to preserving that investment as is more "hard side" management practices such as pavement or bridge management. Corridor management is a process that applies access management principles to highway corridors in an attempt to balance the competing needs of traffic service, safety, and support for land development. This project helped to identify routes that should be given high priority for corridor management. The pilot study in the form of two corridor management case studies provides an analytical process that can be replicated along the other Iowa commuting corridors using commonly available transportation and land use data resources. It also offers a general set of guidelines for the Iowa Department of Transportation to use in the development of its own comprehensive corridor management program.

U.S. 61 From Memorial Park Road in Burlington North to 1 Mile North of IA 78 in Louisa County. Des Moines & Louisa County, Iowa NHS-061-2(50) - 19-58, 2015

Iowa Department of Transportation (Iowa DOT) has re-initiated planning and preliminary design studies to improve U.S. 61 from Memorial Park Road in Burlington north to 1-mile north of IA 78 in Louisa County. The proposed project consists of improving approximately 18 miles of roadway from 2-lanes to 4-lanes and evaluating a potential bypass around Mediapolis.

Temporary Traffic Control Handbook, TR-694, 2016

This handbook provides a broad, easy to understand reference for temporary traffic control in work zones, addressing the safe and efficient accommodation of all road users: motorists, bicyclists, pedestrians, and those with special needs. When impacting a pedestrian facility, provide ten calendar days advance notification to the local jurisdiction and the National Federation of the Blind of Iowa (www.nfbi.org). The information presented is based on standards and guidance in the 2009 Edition of the Manual on Uniform Traffic Control Devices (MUTCD). References to the MUTCD sign designations in this handbook are shown in parentheses, e.g. (W20-1). Not all the recommendations in this handbook will apply to every circumstance faced by local agencies, and each unique situation may not be addressed. Modifications of the typical applications in this handbook will be required to adapt to specific field conditions. Therefore, use engineering judgment, seeking the advice of experienced professionals and supervisors in difficult and complex interpretations. This handbook can be used as a reference for temporary traffic control in work zones on all city or county roadways. However, always check contract documents and local agency requirements for any pertinent modifications.