Traffic Control in Work Zones with Edge Drop-Offs, 2002

Pavement and shoulder edge drop-offs commonly occur in work zones as the result of overlays, pavement replacement, or shoulder construction. The depth of these elevation differentials can vary from approximately one inch when a flexible pavement overlay is applied to several feet where major reconstruction is undertaken. The potential hazards associated with pavement edge differentials depend on several factors including depth of the drop-off, shape of the pavement edge, distance from traveled way, vehicle speed, traffic mix, volume, and other factors. This research was undertaken to review current practices in other states for temporary traffic control strategies addressing lane edge differentials and to analyze crash data and resultant litigation related to edge drop-offs. An objective was to identify cost-effective practices that would minimize the potential for and impacts of edge drop crashes in work zones. Considerable variation in addressing temporary traffic control in work zones with edge drop-off exposure was found among the states surveyed. Crashes related to pavement edge drop-offs in work zones do not commonly occur in the state of Iowa, but some have resulted in significant tort claims and settlements. The use of benefit/cost analysis may provide guidance in selection of an appropriate mitigation and protection of edge drop-off conditions. Development and adoption of guidelines for design of appropriate traffic control for work zones that include edge drop-off exposure, particularly identifying effective use of temporary barrier rail, may be beneficial in Iowa.

Lane Closure Policy Development, Enforcement, and Exceptions: A Survey of Seven State Transportation Agencies, February 2007

Traffic volume increases and an aging infrastructure create the need for reconstruction, rehabilitation, and maintenance of existing facilities. As more motorists feel that delays should be minimal during highway renewal projects, lane closures that reduce capacity through the work zone should not create unreasonable delays. In order to facilitate the determination of when a lane closure is permitted during the day, some state transportation agencies (STAs) have developed lane closure policies, or strategies, that they use as guidance in determining daily permitted lane closure times. Permitted lane closure times define what times of the day, week, or season a lane closure is allowed on a facility and at a specific location or segment. This research addresses the lane closure policies of several STAs that were reputed to have good lane closures policies or strategies and that were selected by the project advisory committee for further research.

Safety Impacts of Pavement Edge Drop-offs, 2006

A vehicle may leave its travel lane for a number of reasons, such as driver error, poor surface conditions, or avoidance of a collision with another vehicle in the travel lane. When a vehicle leaves the travel lane, pavement edge drop-off poses a potential safety hazard because significant vertical differences between surfaces can affect vehicle stability and reduce a driver’s ability to handle the vehicle. Numerous controlled studies have tested driver response to encountering drop-offs under various conditions, including different speeds, vehicle types, drop-off height and shape, and tire scrubbing versus non-scrubbing conditions. The studies evaluated the drivers’ ability to return to and recover within their own travel lane after leaving the roadway and encountering a drop-off. Many of these studies, however, have used professional drivers as test subjects, so results may not always apply to the population of average drivers. Furthermore, test subjects are always briefed on what generally is to be expected and how to respond; thus, the sense of surprise that a truly naïve driver may experience upon realizing that one or two of his or her tires have just dropped off the edge of the pavement, is very likely diminished. Additionally, the studies were carried out under controlled conditions. The actual impact of pavement edge drop-off on drivers’ ability to recover safely once they leave the roadway, however, is not well understood under actual driving conditions. Additionally, little information is available that quantifies the number or severity of crashes that occur where pavement edge drop-off may have been a contributing factor. Without sufficient information about the frequency of edge drop-off-related crashes, agencies are not fully able to measure the economic benefits of investment decisions, evaluate the effectiveness of different treatments to mitigate edge drop-off, or focus maintenance resources. To address these issues, this report details research to quantify the contribution of pavement edge drop-off to crash frequency and severity. Additionally, the study evaluated federal and state guidance in sampling and addressing pavement edge drop-off and quantified the extent of pavement edge drop-off in two states. This study focused on rural two-lane paved roadways with unpaved shoulders, since they are often high speed facilities (55+ mph), have varying levels of maintenance, and are likely to be characterized by adverse roadway conditions such as narrow lanes or no shoulders.

Impacts of Rural Development on Iowa’s Secondary Road Systems, TR-548, September 2010

Today, many of Iowa’s counties are experiencing an increase in rural development. Two specific types of development were focused on for this research: rural residential subdivisions and livestock production operations. Rural residential developments are primarily year round single-family homes, though some are vacation homes. Livestock production in Iowa includes hog, beef, and poultry facilities. These two types of rural development, while obviously very different in nature and incompatible with each other, share one important characteristic: They each generate substantial amounts of new traffic for Iowa’s extensive secondary road system. This research brings together economic, spatial, and legal analysis methods to address the impacts of rural development on the secondary road system and provide county engineers, county supervisors, and state legislators with guidance in addressing the challenges associated with this development.

Midwest Transportation Consortium Annual Program Report, October 2000

The MTC’s main focus is on education and human capital. This focus is in recognition of the fact that the transportation industry, both public and private, in the region served by the MTC faces a serious shortage of well-trained human capital. For this reason, the MTC is in volved in creating totally new transportation education programs at two of its member universities. The University of Northern Iowa (UNI) in Cedar Falls Iowa had no courses or students in transportation when the MTC grant began. During the first year of the grant, UNI’s Geography Department took the lead in developing courses, attracting students, an getting involved a a partner in transportation activities in its service region. A similar start-up effort is now underway at Lincoln University in Jefferson City, Missouri. The MTC has also been able to strengthen and add quality to transportation education efforts at universities in the region that were already leaders in transportation.

Midwest Transportation Consortium Annual Program Report, October 2002

The MTC’s main focus is on education and human capital. This focus is in recognition of the fact that the transportation industry, both public and private, in the region served by the MTC faces a serious shortage of well-trained human capital. For this reason, the MTC is in volved in creating totally new transportation education programs at two of its member universities. The University of Northern Iowa (UNI) in Cedar Falls Iowa had no courses or students in transportation when the MTC grant began. During the first year of the grant, UNI’s Geography Department took the lead in developing courses, attracting students, an getting involved a a partner in transportation activities in its service region. A similar start-up effort is now underway at Lincoln University in Jefferson City, Missouri. The MTC has also been able to strengthen and add quality to transportation education efforts at universities in the region that were already leaders in transportation.

Midwest Transportation Consortium Annual Program Report, October 2004

The MTC’s main focus is on education and human capital. This focus is in recognition of the fact that the transportation industry, both public and private, in the region served by the MTC faces a serious shortage of well-trained human capital. For this reason, the MTC is in volved in creating totally new transportation education programs at two of its member universities. The University of Northern Iowa (UNI) in Cedar Falls Iowa had no courses or students in transportation when the MTC grant began. During the first year of the grant, UNI’s Geography Department took the lead in developing courses, attracting students, an getting involved a a partner in transportation activities in its service region. A similar start-up effort is now underway at Lincoln University in Jefferson City, Missouri. The MTC has also been able to strengthen and add quality to transportation education efforts at universities in the region that were already leaders in transportation.

Preparing Tomorrow's Transportation Workforce: A Midwest Summit, 2010

regional transportation workforce development summits held across the United States in 2009 and 2010 as part of a coordinated initiative to ultimately develop a national strategy to address future transportation workforce issues. The initiative is being led by the U.S. Department of Transportation’s (DOT) Research and Innovative Technology Administration (RITA). This particular summit was hosted by Iowa State University’s Midwest Transportation Consortium (MTC) and Institute for Transportation (InTrans). The purpose of the Midwest summit was to assess the educational and training needs of the future transportation workforce and identify strategies to address those needs across various career paths. It addressed a broad spectrum of topics including strategies to attract women and under-represented minority groups, pre-college opportunities and strategies, post-secondary education, post-college continuing education, professional licensure, and specific industry perspectives. The goals of the summit were (1) to gain an improved understanding of the transportation workforce needs of Iowa and the surrounding states and (2) to identify best practices in addressing the workforce development needs. This event had two tracks: one focused on pre-college education and the other focused primarily on college education and practitioners. Attendees provided a good cross-section of the larger transportation industry. From what was learned at the summit, Iowa State University, like other regional hosts, can develop a “profile of needs” for Iowa including specific job categories over specific time horizons. The summit was also successful in identifying best practices in addressing the workforce needs that can be utilized by us and others as potential tools or in a “national-level list of attributes.” Each regional summit has provided some guidance in developing statewide profiles. The collection of best practices or tools from all the regional summits can be shared and applied to address state (or regional) needs profiles to attract, develop, and retain an effective workforce.

Perception and Interpretation of Advance Warning Signs on County Roads, HR-256, 1984

This research consisted of five laboratory experiments designed to address the following two objectives in an integrated analysis: (1) To discriminate between the symbol Stop Ahead warning sign and a small set of other signs (which included the word-legend Stop Ahead sign); and (2) To analyze sign detection, recognizability, and processing characteristics by drivers. A set of 16 signs was used in each of three experiments. A tachistoscope was used to display each sign image to a respondent for a brief interval in a controlled viewing experiment. The first experiment was designed to test detection of a sign in the driver's visual field; the second experiment was designed to test the driver's ability to recognize a given sign in the visual field; and the third experiment was designed to test the speed and accuracy of a driver's response to each sign as a command to perform a driving action. A fourth experiment tested the meanings drivers associated with an eight-sign subset of the 16 signs used in the first three experiments. A fifth experiment required all persons to select which (if any) signs they considered to be appropriate for use on two scale model county road intersections. The conclusions are that word-legend Stop Ahead signs are more effective driver communication devices than symbol stop-ahead signs; that it is helpful to drivers to have a word plate supplementing the symbol sign if a symbol sign is used; and that the guidance in the Manual on Uniform Traffic Control Devices on the placement of advance warning signs should not supplant engineering judgment in providing proper sign communication at an intersection.

Concrete Pavement Mixture Design and Analysis (MDA): An Innovative Approach To Proportioning Concrete Mixtures, TPF-5(205), 2015

Mixture proportioning is routinely a matter of using a recipe based on a previously produced concrete, rather than adjusting the proportions based on the needs of the mixture and the locally available materials. As budgets grow tighter and increasing attention is being paid to sustainability metrics, greater attention is beginning to be focused on making mixtures that are more efficient in their usage of materials yet do not compromise engineering performance. Therefore, a performance-based mixture proportioning method is needed to provide the desired concrete properties for a given project specification. The proposed method should be user friendly, easy to apply in practice, and flexible in terms of allowing a wide range of material selection. The objective of this study is to further develop an innovative performance-based mixture proportioning method by analyzing the relationships between the selected mix characteristics and their corresponding effects on tested properties. The proposed method will provide step-by-step instructions to guide the selection of required aggregate and paste systems based on the performance requirements. Although the provided guidance in this report is primarily for concrete pavements, the same approach can be applied to other concrete applications as well.

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.

Draft Project Management Update to the Iowa DOT Project Development Manual, 2016

This work supported drafting project management guidance for the Iowa Department of Transportation (DOT). The goal is to incorporate a greater focus on project management in their project development process. A technical advisory committee (TAC) was assembled to accomplish this effort. The TAC took into consideration the current status of project management with the Iowa DOT, their experience during the demonstration workshop held in Iowa as part of the implementation assistance they received, the project management peer exchange hosted by the Iowa DOT, and additional examples of project management that were presented. With this basis, the TAC participated in a number of discussions to develop draft guidance for the foundation of a Project Management Office (PMO) within the Iowa DOT. The final report describes the process that was used in establishing this guidance. The report details the decisions and decision process that the TAC employed in this endeavor and provides additional thoughts and insight into the draft guidance. Appendix A includes the draft guidance in the form of PMO function details and detailed lists of project management roles and responsibilities. Appendix B includes a starter list of project management resources for the PMO.