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Project Details
STATUS

Completed

START DATE

02/01/10

END DATE

11/11/11

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium
U.S. DOT RITA

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

Co-Principal Investigator
Tom McDonald

Safety Circuit Rider

About the research

Red light running (RLR) is a problem in the US that has resulted in 165,000 injuries and 907 fatalities annually. In Iowa, RLR-related crashes make up 24.5 percent of all crashes and account for 31.7 percent of fatal and major injury crashes at signalized intersections.

RLR crashes are a safety concern due to the increased likelihood of injury compared to other types of crashes. One tool used to combat red light running is automated enforcement in the form of RLR cameras. Automated enforcement, while effective, is often controversial.

Cedar Rapids, Iowa installed RLR and speeding cameras at seven intersections across the city. The intersections were chosen based on crash rates and whether cameras could feasibly be placed at the intersection approaches.

The cameras were placed starting in February 2010 with the last one becoming operational in December 2010. An analysis of the effect of the cameras on safety at these intersections was determined prudent in helping to justify the installation and effectiveness of the cameras.

The objective of this research was to assess the safety effectiveness of the RLR program that has been implemented in Cedar Rapids. This was accomplished by analyzing data to determine changes in the following metrics:

  • Reductions in red light violation rates based on overall changes, time of day changes, and changes by lane
  • Effectiveness of the cameras over time
  • Time in which those running the red light enter the intersection
  • Changes in the average headway between vehicles entering the intersection

Funding Sources:
Iowa Department of Transportation ($15,000.00)
Midwest Transportation Consortium ($25,000.00)
U.S. DOT RITA
Total: $40,000.00

Project Details
STATUS

Completed

PROJECT NUMBER

TR-579, 07-311, 08-320

START DATE

11/01/08

END DATE

10/30/13

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Federal Highway Administration
Iowa Department of Transportation
Iowa Highway Research Board
Midwest Transportation Consortium
Minnesota Department of Transportation
U.S. DOT RITA

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

Co-Principal Investigator
Omar Smadi

Director, CTRE

Co-Principal Investigator
Neal Hawkins

Associate Director, InTrans

Student Researcher(s)
Huishan Duan

About the research

The main goal of this research is to evaluate the effectiveness of dynamic speed feedback signs and other low-cost strategies to reduce speeds and crashes on curves. Research results will provide traffic safety and county engineers and other professionals with additional tools to more effectively manage speeds and decrease crashes on horizontal curves on rural roadways.


Funding Sources:
Federal Highway Administration
Iowa Department of Transportation ($80,000.00)
Iowa Highway Research Board
Midwest Transportation Consortium
Minnesota Department of Transportation
U.S. DOT RITA
Total: $80,000.00

Project Details
STATUS

Completed

START DATE

09/01/09

END DATE

03/31/11

FOCUS AREAS

Infrastructure, Safety

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Midwest Transportation Consortium

Researchers
Principal Investigator
Omar Smadi

Director, CTRE

Co-Principal Investigator
Konstantina Gkritza
Co-Principal Investigator
Neal Hawkins

Associate Director, InTrans

Co-Principal Investigator
Başak Aldemir Bektaş

About the research

Incorporating safety performance measures into asset management can assist transportation agencies in managing their aging assets efficiently and improve system-wide safety. Past research has revealed the relationship between individual asset performance and safety, but the relationship between combined measures of operational asset condition and safety performance has not been explored.

This project investigates the effect of pavement marking retroreflectivity and pavement condition on safety in a multi-objective manner. Data on one-mile segments for all Iowa primary roads from 2004 through 2009 were collected from the Iowa Department of Transportation and integrated using linear referencing.

An asset condition index (ACI) was estimated for the road segments by scoring and weighting individual components.

Statistical models were then developed to estimate the relationship between ACI and expected number of crashes, while accounting for exposure (average daily traffic).

Finally, the researchers evaluated alternative treatment strategies for pavements and pavement markings using benefit-cost ratio analysis, taking into account corresponding treatment costs and safety benefits in terms of crash reduction (number of crashes proportionate to crash severity).


Funding Sources:
Midwest Transportation Consortium ($100,000.00)
Total: $100,000.00

Project Details
STATUS

Completed

START DATE

08/01/09

END DATE

09/28/12

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Midwest Transportation Consortium

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

About the research

This study provides better information about the effectiveness of rural roadway safety countermeasures with a focus on lane departures. The main emphasis of the research was to conduct a crash surrogate analysis for common road departure events and develop a model that can be used to predict and mitigate road departures.


Funding Sources:
Midwest Transportation Consortium ($94,874.00)
Total: $94,874.00

Project Details
STATUS

Completed

PROJECT NUMBER

09-358

START DATE

08/15/09

END DATE

03/31/11

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE, Iowa LTAP
SPONSORS

Federal Highway Administration
Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

Co-Principal Investigator
Tom McDonald

Safety Circuit Rider

Co-Principal Investigator
Robert Sperry
Student Researcher(s)
Evan Vencil

About the research

Pavement edge drop-off can be a serious safety concern when a vehicle leaves the paved roadway surface and encounters a significant vertical elevation difference between the paved roadway and adjacent unpaved shoulder. Edge drop-offs are potential safety hazards, because significant vertical differences between surfaces can reduce vehicle stability and affect the driver’s ability to control their vehicle when inadvertently leaving the paved driving area.

In addition, scrubbing between the pavement edge and tire can result in loss of control.  The Federal Highway Administration (FHWA) (2010) estimates that 160 fatalities and more than 11,000 injuries annually are related to unsafe pavement edges.

The FHWA developed the Safety Edge based on results of research indicating that a sloped pavement edge surface could more easily be traversed by the driver of a vehicle leaving its lane and attempting to remount the pavement edge. The Safety Edge is a design feature that creates about a 30 degree fillet along the outermost edge of the paved section of the roadway. The Safety Edge is most commonly placed during hot-mix asphalt (HMA) paving, using a device that shapes and consolidates the asphalt material at the pavement edge into about a 30 degree fillet.  The shape created by the Safety Edge reduces the likelihood that tire scrubbing will occur and provides a gradual, rather than an abrupt, transition back to the roadway as drivers of errant vehicles remount the pavement surface.

Because use of the Safety Edge was relatively new to Iowa, the Iowa Department of Transportation (DOT) and the FHWA – Iowa Division commissioned the Center for Transportation Research and Education (CTRE) at Iowa State University (ISU) to develop educational materials, market the Safety Edge to Iowa counties, and conduct some early analyses of the Safety Edge.

One of the project objectives was to encourage use of the Safety Edge by marketing it to state and local agencies in Iowa. With input from the advisory group, a list of potential projects where the Safety Edge could be applied was developed. A survey of counties identified planned projects for the 2010 construction season. These counties were then contacted to determine interest in using the Safety Edge concept. Participating Iowa counties added the Safety Edge to projects by contract plans or extra work orders, depending on project letting dates.

When requested, the CTRE team provided various types of technical assistance, including project design recommendations, attendance at pre-construction meetings, open houses to demonstrate the Safety Edge, loan of equipment for actual roadway construction with the Safety Edge, troubleshooting, and monitoring of work. The CTRE research team also provided technical assistance as needed to agencies where the Safety Edge was used.

The project resulted in a final report and three deliverables which can be used nationally by state, county and local roadway agencies.

1. Training Material for Local Technical Assistance Programs (LTAP): The CTRE team worked with a number of counties during the 2010 construction season to educate agencies and contractors and provide technical assistance before and during construction. The team developed materials to educate counties and contractors who had not used the Safety Edge before. Additionally, during the season, the team worked with agencies to resolve a number of problems that occurred during construction. Discussions with other state DOT and agencies indicated that they had also experienced similar problems but had not had the resources to look into or resolve the problems.

Further conversation with the Iowa LTAP program indicated a need for resources which could be used to provide training for local agencies. Consequently a set of outreach materials were developed. This included a PowerPoint presentation which can be used for training and several tech transfer briefs. The material could be used by any Local Technical Assistance Program or roadway agency for training and includes the following information: (1) description of why pavement edge drop-off is a problem; (2) description of what the Safety Edge is; (3) quality assurance during construction; (4) contractor benefits; (5) lessons learned; (6) estimating additional cost of material; and (7) recommendations.

The team worked with an advisory panel which included FHWA, the Iowa DOT, Iowa counties, the Asphalt Paving Association of Iowa, the Iowa Concrete Paving Association, and several construction counties. As a result, the information has been vetted by a large group of knowledgeable peers.

2. Development of PCC Design Standard for the Safety Edge: At the commencement of this project, there were no properly designed applications of the Safety Edge on Portland Cement Concrete, (PCC) paving projects nationally as far as CTRE researchers or advisory team members were aware. With encouragement from FHWA, the CTRE team and the Iowa DOT worked to develop PCC Safety Edge design standards and specifications. This resulted in the first national demonstration of the Safety Edge with PCC on E-34 in Jones/Linn County, Iowa.

3. Iowa Lane Departure Strategic Plan: Results of the project also resulted in a chapter which was included in the Iowa Lane Departure Strategic Plan. The document is proposed guidance to reduce the number of roadway departure crashes in Iowa using countermeasures identified in the guide. The guide is used by the Iowa DOT, Iowa counties and cities. The material in the chapter supplements material developed for training and outreach.

Project Details
STATUS

Completed

PROJECT NUMBER

09-359

START DATE

11/15/09

END DATE

06/04/11

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE, MTC, SWZDI
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium
Smart Work Zone Deployment Initiative

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

About the research

The purpose of this project was to determine which driver behaviors result in the greatest reduction of capacity with work zone lane closures. Traffic and safety experts believe that driver behaviors, such as forcing late mergers, tailgating, queue jumping in the closed lane or on the shoulder, and other aggressive behaviors have the greatest impact on maximum flow rates. Other behaviors that create excessive headways or slow speeds can also reduce maximum flow in the taper. The objectives of this project were to identify and document driver behaviors that are the most detrimental to work zone traffic flow and safety.

Data were collected at freeway work zones for six days to identify behaviors that affected work zone safety and operations, which included forced and late merges, lane straddling, and queue jumping. Queue jumping occurs when a driver already in the open lane decides to jockey for a better position by moving to the closing lane and passes one or more vehicles before merging back to the open lane.

A total of 30 vehicles queue jumped during the study period. However, vehicles only improved their position in most cases by one vehicle. The queue jumping also resulted in four forced merges, eight late merges, and four late forced merges, indicating that queue jumping has an impact on operations. In addition, queue jumping appeared to evoke aggressive behavior by other drivers, which was manifested by lane straddling and, in some cases, vehicles physically trying to block queue jumpers.

Lane straddling occurs when drivers move to straddle the lane line separating the open and closing lanes with their vehicles. Drivers who lane straddle attempt to prevent vehicles behind them from late merging or moving ahead of them in the queue.

The lane straddling incidents observed in this study often involved several vehicles. Of the 51 incidents that were noted, lane straddling resulted in one forced merge, two late merges, and 14 forced late merges. The main operation impact is that lane straddling creates forced merges that may not have otherwise occurred. In addition, in several cases, drivers who engaged in lane straddling in this study ended up slowing down the entire queue behind them, as they attempted to prevent a driver behind them from using the space they left when they moved over to lane straddle.

This study identified behaviors that compromise safety in work zones. Forced merges, which are discussed as operational problems, are also safety problems, because a driver behind a forced merge has to slow or, in some cases, take some evasive action to avoid colliding with the merging vehicle. Queue jumping also compromises safety, because it creates forced merges and often resulted, in this study, in aggressive actions by other drivers.

Lane straddling can also compromise safety by creating forced merges that may not have otherwise occurred. Lane straddling also resulted in several other safety-compromising behaviors: drivers using the shoulder to pass lane-straddling vehicles, drivers attempting to merge into the space previously occupied by the lane-straddling vehicle and resulting in the lane-straddling driver attempting to physically block the merging vehicle, and, in one case, drivers racing abreast until reaching the arrow board, where a forced merge occurred.


Funding Sources:
Iowa Department of Transportation ($30,000.00)
Midwest Transportation Consortium
Smart Work Zone Deployment Initiative
Total: $30,000.00

Project Details
STATUS

Completed

START DATE

07/01/09

END DATE

06/30/10

RESEARCH CENTERS InTrans, CTRE
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Konstantina Gkritza
Student Researcher(s)
Wei Zhang

About the research

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.

Project Details
STATUS

Completed

START DATE

01/01/07

END DATE

06/30/09

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Midwest Transportation Consortium

Researchers
Principal Investigator
Tim Strauss

University of Northern Iowa

About the research

This project examines the potential of, and constraints on, the integration of transportation safety databases in a spatially-referenced geographic information systems (GIS) environment. The project focuses specifically on the analysis of crash records and driver records. The objective of such database integration is to facilitate the improved analysis of issues related to transportation safety. The objective of such database integration is to facilitate improved analyses of issues related to transportation safety.

This report begins with a review of existing databases. These include traffic records databases and other databases that may enhance safety analyses. The report then outlines several existing applications, which are typically in a non-spatial framework, of integrated databases related to transportation safety. The report then focuses on existing and potential applications that make use of spatially-referenced information within these databases.

Despite the promise of spatially-referenced data integration and analysis, there are several concerns to address. Possible constraints on spatially-referenced database integration and analysis involve technical issues related to the integration of spatial data files and the data?s representation in GIS; methodological issues concerning the use of spatial data; administrative concerns regarding data collection, management, and linkage; and legal and ethical concerns related to the use of confidential information. This report attempts to identify strategies to address these concerns and concludes with recommendations for future activities related to the integration of spatially-referenced data for transportation safety.


Funding Sources:
Midwest Transportation Consortium ($14,987.00)
Total: $14,987.00

Project Details
STATUS

Completed

START DATE

03/01/08

END DATE

06/30/09

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Midwest Transportation Consortium

Researchers
Principal Investigator
Jennifer Shane

Director, CMAT

Co-Principal Investigator
Kelly Strong

Associate Director, Contracts and Project Management

Student Researcher(s)
Daniel Enz

About the research

The goal of this research is to mitigate the risk of highway accidents (crashes) and fatalities in work zones. The approach of this research has been to address the mitigation of work zone crashes through the creation of a formal risk management model to be utilized during the construction management and administration of highway projects for all stages of the project life-cycle. The result of these efforts is realized through the design of an integrated risk management model. A standard risk management model has three components: risk identification, risk analysis, and risk response. The risks are identified by the factors that contribute to work zone crashes. The risk analysis involves understanding the tendency of a hazard to influence the frequency or severity of a loss, and the risk response relates to the appropriate countermeasures to the factors that contribute to work zone crashes. The number of hazards and mitigation strategies corresponding to work zone crashes can be substantial.

The intent of this research is to develop a formalized risk management plan to identify potential hazards on plans, designs, or jobsites and to cue a risk response to the hazards. Mitigation strategies may take the form of a mitigation method (alert motorist, assist worker/motorist, control motorist, inform motorist, and protect worker/motorist).

The results of this research will be a formal step-by-step methodology to be utilized by managers and decision makers. Each stage of the project life-cycle (or Project Development Process) will provide a checklist of hazards and mitigation strategies.

This research will also provide a qualitative method to assess the likelihood and severity of a hazard or multiple hazards on a roadway work zone. This research is intended to provide a holistic approach to risk management that is to be integrated into the existing corporate structure and not to be considered a standalone program. This integrated approach will allow a formalized procedure to be utilized by any member of an organization during all phases of the construction project life-cycle.


Funding Sources:
Midwest Transportation Consortium ($60,774.00)
Total: $60,774.00

Project Details
STATUS

Completed

START DATE

05/01/07

END DATE

04/19/09

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium
University of Northern Iowa

Researchers
Principal Investigator
Tim Strauss

University of Northern Iowa

About the research

This project analyzes the characteristics and spatial distributions of motor vehicle crash types in order to evaluate the degree and scale of their spatial clustering. Crashes occur as the result of a variety of vehicle, roadway, and human factors and thus vary in their clustering behavior. Clustering can occur at a variety of scales, from the intersection level, to the corridor level, to the area level. Conversely, other crash types are less linked to geographic factors and are more spatially ?random.? The degree and scale of clustering have implications for the use of strategies to promote transportation safety.

In this project, Iowa’s crash database, geographic information systems, and recent advances in spatial statistics methodologies and software tools were used to analyze the degree and spatial scale of clustering for several crash types within the counties of the Iowa Northland Regional Council of Governments. A statistical measure called the K function was used to analyze the clustering behavior of crashes. Several methodological issues, related to the application of this spatial statistical technique in the context of motor vehicle crashes on a road network, were identified and addressed. These methods facilitated the identification of crash clusters at appropriate scales of analysis for each crash type. This clustering information is useful for improving transportation safety through focused countermeasures directly linked to crash causes and the spatial extent of identified problem locations, as well as through the identification of less location-based crash types better suited to non-spatial countermeasures.

The results of the K function analysis point to the usefulness of the procedure in identifying the degree and scale at which crashes cluster, or do not cluster, relative to each other. Moreover, for many individual crash types, different patterns and processes and potentially different countermeasures appeared at different scales of analysis. This finding highlights the importance of scale considerations in problem identification and countermeasure formulation.


Funding Sources:
Iowa Department of Transportation
Midwest Transportation Consortium
University of Northern Iowa

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