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Project Details
STATUS

Completed

START DATE

06/01/07

END DATE

12/31/11

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Reginald Souleyrette
Co-Principal Investigator
Chris Albrecht
Co-Principal Investigator
David Plazak

Associate Director for Policy

Student Researcher(s)
Joshua Hochstein

About the research

For several years, the Iowa Department of Transportation has constructed bypasses along rural highways. Most bypasses were constructed on the state?s Commercial Industrial Network (CIN). Now that work on the CIN has been completed and the system is open to traffic, it is possible to study the impacts of bypasses. In the past, construction of highway bypasses has led community residents and business people to raise concerns about the loss of business activity. For policy development purposes, it is essential to understand the impacts that a bypass might have on safety, the community, and economics. By researching these impacts, policies can be produced to help to alleviate any negative impacts and create a better system that is ultimately more cost-effective.

This study found that the use of trade area analysis does not provide proof that a bypass can positively or negatively impact the economy of a rural community. The analysis did show that, even though the population of a community may be stable for several years and per capita income is increasing, sales leakage still occurs. The literature, site visits, and data make it is apparent that a bypass can positively affect a community. Some conditions that would need to exist in order to maximize a positive impact include the installation of signage along the bypass directing travelers to businesses and services in the community, community or regional plans that include the bypass in future land development scenarios, and businesses adjusting their business plans to attract bypass users. In addition, how proactive a community is in adapting to the bypass will determine the kinds of effects felt in the community.

Results of statistical safety analysis indicate that, at least when crashes are separated by severity, bypasses with at-grade accesses appear to perform more poorly than either the bypasses with fully separated accesses or with a mix of at-grade and fully separated accesses. However, the benefit in terms of improved safety of bypasses with fully separated accesses relative to bypasses with a mixed type of accesses is not statistically conclusive.


Funding Sources:
Iowa Department of Transportation
Midwest Transportation Consortium

Project Details
STATUS

Completed

START DATE

01/01/10

END DATE

12/31/11

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Reginald Souleyrette
Co-Principal Investigator
Tom Maze

Transportation Engineer

Student Researcher(s)
Joshua Hochstein

About the research

The ultimate goal of this research was to provide improved design guidance for J-turn intersections by learning more about the safety and operational consequences of including or excluding certain geometric design features under various traffic volume conditions.

The proposed methodology to accomplish this research objective was to use the VisSim micro-simulation software package in conjunction with Federal Highway Administration (FHWA) Surrogate Safety Assessment Model (SSAM).

Three alternative high-speed rural expressway intersection designs were modeled previously in VisSim and used to accomplish this analysis. This report examines the use of SSAM for performing a conflict analysis, comparing the safety consequences of alternative designs, and developing conflict and/or crash modification factors. A conflict analysis methodology using the SSAM software was developed and refined. The refined conflict analysis methodology is included in this report.


Funding Sources:
Iowa Department of Transportation ($58,800.00)
Midwest Transportation Consortium ($26,465.00)
Total: $85,265.00

Project Details
STATUS

Completed

PROJECT NUMBER

07-305

START DATE

11/01/07

END DATE

11/30/11

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE
SPONSORS

Federal Highway Administration
Iowa Department of Transportation
Iowa Highway Research Board
Midwest Transportation Consortium

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

Co-Principal Investigator
Tom McDonald

Safety Circuit Rider

About the research

Single-vehicle run-off-road crashes are the most common crash type on rural two-lane Iowa roads. Rumble strips have proven effective in mitigating these crashes, but the strips are commonly installed in paved shoulders on higher-volume roads that are owned by the State of Iowa. Lower-volume paved rural roads owned by local agencies do not commonly feature paved shoulders but frequently experience run-off-road crashes.

This project involved installing rumble stripes, which are a combination of conventional rumble strips with a painted edge line placed on the surface of the milled area, along the edge of the travel lanes, but at a narrow width to avoid possible intrusion into the normal vehicle travel paths.

The research described in this report was part of a project funded by the Federal Highway Administration, Iowa Highway Research Board, and Iowa Department of Transportation to evaluate the effectiveness of edge-line rumble strips in Iowa. The project evaluated the effectiveness of rumble stripes in reducing run-off-road crashes and in improving the longevity and wet-weather visibility of edge-line markings.

This project consisted of two phases. The first phase was to select pilot study locations, select a set of test sites, install rumble stripes, summarize lessons learned during installation, and provide a preliminary assessment of the rumble stripes’ performance.

The purpose of this report was to document results from Phase II. A before and after crash analysis was conducted to assess whether use of the treatment had resulted in fewer crashes. However, due to low sample size, results of the analysis were inconclusive. Lateral position was also evaluated before and after installation of the treatment to determine whether vehicles engaged in better lane keeping. Pavement marking wear was also assessed.

Project Details
STATUS

Completed

START DATE

04/01/07

END DATE

10/31/10

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Neal Hawkins

Associate Director, InTrans

Co-Principal Investigator
Zachary Hans

Director, CWIMS

Co-Principal Investigator
Omar Smadi

Director, CTRE

About the research

Develop a sign and pavement marking management system which –Improves the quality of signage and pavement marking out on the roadway network. –Improves the ability to manage all aspects of each asset from placement through end of life. –Improves the ability to budget for these key assets on a statewide basis. –Provides a tool for decision makers to do asset related scenario planning regarding funding needs, life cycle, quality, and material selection. Abstract The Iowa Department of Transportation (Iowa DOT) is committed to infrastructure management and understands the significant potential benefits from implementing practical management systems. This work will help the DOT with the development of their pavement marking and sign management systems through the MTC project. The MTC portion of this project (described below) will focus on tool development, data integration (GIS/GPS) and an implementation plan that allows the DOT to integrate these tools into daily operations. The Iowa DOT matching funds will be used to complete the implementation and operation phases of the systems.


Funding Sources:
Iowa Department of Transportation
Midwest Transportation Consortium

Project Details
STATUS

Completed

PROJECT NUMBER

TR-577, 07-304

START DATE

11/01/07

END DATE

07/31/09

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Federal Highway Administration
Iowa Department of Transportation
Iowa Highway Research Board
Midwest Transportation Consortium

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

Co-Principal Investigator
Tom McDonald

Safety Circuit Rider

About the research

Single-vehicle run-off-road crashes are the most common crash type on rural two-lane Iowa roads. Rumble strips have been proven effective in mitigating these crashes, but these strips are commonly installed in paved shoulders adjacent to higher-volume roads owned by the State of Iowa. Lower-volume paved rural roads owned by local agencies do not commonly feature paved shoulders but frequently experience run-off-road crashes. This project involved installing ?rumble stripes,? which are a combination of conventional rumble strips with a painted edge line placed on the surface of the milled area, along the edge of the travel lanes but at a narrow width to avoid possible intrusion into the normal vehicle travel paths.

Candidate locations were selected from a list of paved local rural roads that were most recently listed in the top 5% of roads for run-off-road crashes in Iowa. Horizontal curves were the most favored locations for rumble stripe installation because they commonly experience roadway departure crashes.

The research described in this report was part of a project funded by the Federal Highway Administration, Iowa Highway Research Board, and Iowa Department of Transportation to evaluate the effectiveness of edge line rumble strips in Iowa. The project evaluated the effectiveness of ?rumble stripes? in reducing run-off-road crashes and in improving the longevity and wet weather visibility of edge line markings. This project consists of two phases. The first phase was to select pilot study locations, select a set of test sites, install rumble stripes, summarize lessons learned during installation, and provide a preliminary assessment of the rumble stripes? performance. This information is summarized in this report. The purpose of the second phase is to provide a more long-term assessment of the performance of the pavement markings, conduct preliminary crash assessments, and evaluate lane keeping. This will result in a forthcoming second report

Project Details
STATUS

Completed

START DATE

10/01/07

END DATE

09/06/11

RESEARCH CENTERS InTrans, CTRE
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Shauna Hallmark

Director, InTrans

Student Researcher(s)
Nicole Oneyear

About the research

This study documents the speed reduction impacts of two dynamic, electronic school zone speed limit signs at United Community Schools between Ames and Boone, Iowa. The school facility is situated along US Highway 30, a rural four-lane divided expressway.

Due to concerns about high speeds in the area, the Iowa Department of Transportation (DOT) decided to replace the original static school zone speed limit signs, which had flashing beacons during school start and dismissal times, with electronic speed signs that only display the reduced school speed limit of 55 mph during school arrival and dismissal times.

The Center for Transportation Research and Education (CTRE) at Iowa State University (ISU) conducted a speed evaluation of the area one week before and then 1 month, 7 months, and 14 or 15 months after the new signs were installed.

Overall, the new dynamic school zone speed limit signs were more effective in reducing speeds than the original static signs with flashing beacons in the 1 month after period. During the 7 and 14 month after period, speeds increased slightly for the eastbound direction of traffic. However, the increases were consistent with overall speed increases that occurred independent of the signs.

The dynamic, electronic signs were effective for the westbound direction of traffic for all time periods and for both start and dismissal times. Even though only modest changes in mean and 85th percentile speeds occurred, with the speed decreases, the number of vehicles exceeding the school speed limit decreased significantly, indicating the signs had a significant impact on high-end speeders.

Project Details
STATUS

Completed

START DATE

01/01/10

END DATE

08/31/11

RESEARCH CENTERS InTrans, CTRE, CWIMS, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Zachary Hans

Director, CWIMS

Co-Principal Investigator
Neal Hawkins

Associate Director, InTrans

About the research

Highway agencies spend millions of dollars to ensure safe and efficient winter travel. However, the effectiveness of winter weather maintenance practices on safety and mobility are somewhat difficult to quantify.

Phase I of this project investigated opportunities for improving traffic safety on state-maintained roads in Iowa during winter weather conditions.

The primary objective was to develop several preliminary means for the Iowa Department of Transportation (DOT) to identify locations of possible interest systematically with respect to winter weather-related safety performance based on crash history.

Specifically, metrics were developed to assist in identifying possible habitual, winter weather-related crash sites on state-maintained rural highways in Iowa. In addition, the current state of practice, for both domestic and international highway agency practices, regarding integration of traffic safety- and mobility-related data in winter maintenance activities and performance measures were investigated. This investigation also included previous research efforts.

Finally, a preliminary work plan, focusing on systematic use of safety-related data in support of winter maintenance activities and site evaluation, was prepared.


Funding Sources:
Iowa Department of Transportation ($35,000.00)
Midwest Transportation Consortium ($35,000.00)
Total: $70,000.00

Project Details
STATUS

Completed

START DATE

01/01/10

END DATE

08/31/11

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

City of Ames, Iowa
Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Reginald Souleyrette
Co-Principal Investigator
Konstantina Gkritza

About the research

The consideration of safety in metropolitan planning is a requirement of the Federal Highway legislation (SAFETEA-LU). No specific guidance has yet been provided to MPOs on how safety should be considered (qualitatively or quantitatively), nor where or at what level it should be considered (project, corridor or regionwide). The lack of guidance is particularly challenging to small planning agencies. In recent years, several safety analysis techniques have been developed that may be applicable to explicitly incorporate safety objectives in the planning process. This project proposes to investigate road assessment program and risk mapping strategies that may be applicable to small area metropolitan safety planning.


Funding Sources:
City of Ames ($70,000.00)
Iowa Department of Transportation
Midwest Transportation Consortium ($25,089.00)
Total: $95,089.00

Project Details
STATUS

Completed

START DATE

03/01/09

END DATE

08/31/11

RESEARCH CENTERS InTrans, CTRE
SPONSORS

City of Ames, Iowa
Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Konstantina Gkritza
Co-Principal Investigator
Reginald Souleyrette

About the research

The historically-reactive approach to identifying safety problems and mitigating them involves selecting black spots or hot spots by ranking locations based on crash frequency and severity. The approach focuses mainly on the corridor level without taking the exposure rate (vehicle miles traveled) and socio-demographics information of the study area, which are very important in the transportation planning process, into consideration. A larger study analysis unit at the Transportation Analysis Zone (TAZ) level or the network planning level should be used to address the needs of development of the community in the future and incorporate safety into the long-range transportation planning process.

In this study, existing planning tools (such as the PLANSAFE models presented in NCHRP Report 546) were evaluated for forecasting safety in small and medium-sized communities, particularly as related to changes in socio-demographics characteristics, traffic demand, road network, and countermeasures. The research also evaluated the applicability of the Empirical Bayes (EB) method to network-level analysis. In addition, application of the United States Road Assessment Program (usRAP) protocols at the local urban road network level was investigated.

This research evaluated the applicability of these three methods for the City of Ames, Iowa. The outcome of this research is a systematic process and framework for considering road safety issues explicitly in the small and medium-sized community transportation planning process and for quantifying the safety impacts of new developments and policy programs. More specifically, quantitative safety may be incorporated into the planning process, through effective visualization and increased awareness of safety issues (usRAP), the identification of high-risk locations with potential for improvement, (usRAP maps and EB), countermeasures for high-risk locations (EB before and after study and PLANSAFE), and socio-economic and demographic induced changes at the planning-level (PLANSAFE).

Project Details
STATUS

Completed

START DATE

03/01/07

END DATE

07/31/11

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

Iowa Department of Transportation
Midwest Transportation Consortium

Researchers
Principal Investigator
Tom Maze

Transportation Engineer

Co-Principal Investigator
Reginald Souleyrette

About the research

This document is intended to be a guide for planning-level decisions concerning safety issues and subsequent potential improvements at rural expressway intersections. It presents the gamut of safety treatment options and available strategies that have been employed in an attempt to reduce the number and severity of collisions at unsignalized rural expressway intersections. Treatment strategies have been categorized within 9 emphasis areas (A through I) similar to those within NCHRP 500, Volume 5 2; however, the focus here is directly on unsignalized rural expressway intersections rather than unsignalized intersections in general. Some strategies may qualify for multiple categories, but have been placed in the category judged to be the most applicable.


Funding Sources:
Iowa Department of Transportation
Midwest Transportation Consortium

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