CLOSE OVERLAY
Project Details
STATUS

In-Progress

START DATE

09/01/23

END DATE

02/28/26

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, AMPP
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

PARTNERS

University of Iowa

Researchers
Principal Investigator
Hosin "David" Lee
Principal Investigator
Chris Williams

Director, AMPP

About the research

The main purpose of this research is to develop a comprehensive asphalt recycling strategy for high RAM mix up to 50% in consultation with surrounding state departments of transportation (DOTs), along with cities and counties, by performing the following tasks:

  • Evaluate existing and new high RAP projects and test sections
  • Select a cracking test procedure as a performance test
  • Conduct performance tests of high RAP mixtures up to 50%
  • Develop an approval process for rejuvenators
  • Evaluate warm mix asphalt (WMA) with a high RAM content
  • Develop a comprehensive asphalt pavement recycling strategy
Project Details
STATUS

Completed

PROJECT NUMBER

TR-770

START DATE

01/01/19

END DATE

03/31/22

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, AMPP
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Hosin "David" Lee
Principal Investigator
Chris Williams

Director, AMPP

About the research

The main purpose of the proposed research is to develop a mix design procedure for high RAM mixtures with both rejuvenators and fractionated RAM materials for the Iowa Department of Transportation (DOT) and local public agencies by thoroughly understanding complex interactions between fractionated RAM and rejuvenators. The main objectives of this research are to: (1) examine the effects of various rejuvenators and different methods of RAP stockpile fractionation on the volumetric mix design properties, (2) evaluate long-term oven aging of both laboratory and field rejuvenated/fractionated high RAM mixtures and (3) develop specifications for evaluating asphalt mixtures with rejuvenators and high fractionated RAM contents.

Project Details
STATUS

In-Progress

PROJECT NUMBER

24-887, TPF-5(438)--72-00

START DATE

03/01/24

END DATE

05/31/25

SPONSORS

Iowa Department of Transportation
Smart Work Zone Deployment Initiative

Researchers
Principal Investigator
Guillermo Basulto-Elias

Research Scientist, CTRE

Co-Principal Investigator
Skylar Knickerbocker

Research Scientist, CTRE

About the research

The research team aims to create an analytical tool for work zones by identifying essential performance indicators and measurements. To achieve this, a thorough literature review will be conducted, consolidating prior research and state-level initiatives that relate to work zone performance. Based on the findings, the team will develop a comprehensive list of performance metrics and summarize the results in a document. Finally, these key measurements and performance indicators will be used to create an analytical tool for work zones that presents performance data in easy-to-read tables, diagrams, and downloadable reports. This will generate performance analyses after stakeholders upload or link their data sources.

Project Details
STATUS

In-Progress

PROJECT NUMBER

24-883

START DATE

01/15/24

END DATE

01/31/27

RESEARCH CENTERS InTrans, CMAT
SPONSORS

Iowa Department of Transportation

PARTNERS

BIO‐WEST, HDR, Horrocks, Fehr‐Graham

Researchers
Principal Investigator
Roy Sturgill

Construction Engineer, CMAT

About the research

The Iowa Department of Transportation (DOT) received Federal funding via an AID Grant to execute activities proposed within the Iowa Digital Delivery Strategic Plan published in November 2022. The AID Grant project has four major objectives:

  1. Prepare and deliver a detailed implementation and deployment plan to execute the tactical goals prioritized in the Iowa DOT Digital Delivery Roadmap
  2. Improve asset management in the department by integrating information beyond digital as-builts and geospatial information
  3. Deploy and document projects to pilot comprehensive use cases for digital delivery (DD) and transitioning into digital lifecycle workflows to support asset management strategies
  4. Conduct internal and external stakeholder engagement and outreach

The work will be performed by a team of several consultants, including BIO‐WEST, HDR, Horrocks, Fehr‐Graham, and Iowa State University.

Project Details
STATUS

In-Progress

PROJECT NUMBER

24-882, HR-2049

START DATE

01/01/24

END DATE

12/31/24

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CP Tech Center, PROSPER
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Halil Ceylan

Director, PROSPER

Co-Principal Investigator
Sunghwan Kim

Associate Director, PROSPER

Co-Principal Investigator
Peter Taylor

Director, CP Tech Center

Co-Principal Investigator
Dan King

Research Engineer, CP Tech Center

About the research

An electrically conductive concrete (ECON) heated pavement system (HPS) utilizes the inherent electrical resistance of concrete to maintain the pavement surface at above-freezing temperatures and thus prevent snow and ice accumulation on the surface. Such a sustainable concrete pavement system can improve its infrastructure resiliency by allowing it to be safe, open, and accessible during even harsh winter storms. The primary objective of this project is to to enhance the practicality of the ECON mix design and ECON HPS field implementation by conducting necessary tests to establish a defined range of electrical conductivity compliant with national electrical safety specifications for executing the construction of the Iowa City Bus Stop Enhancement Project. This will be achieved through execution of the following primary tasks: (1) project management; (2) formulating robust production, transportation, and quality control/assurance (QC/QA) protocols; (3) determining electrical safety protocols; (4) developing implementation plans with recommendations; and (5) producing a final project report. The outcomes of this project will include both best-practice guidance on the steadfast and uniform quality of ECON mixture production as well as a defined range of electrical conductivity for the ECON HPS, ensuring both performance and safety. Such outcomes could result in successful implementation of the ECON HPS for the Iowa City Bus Stop Enhancement Project.

Project Details
STATUS

In-Progress

PROJECT NUMBER

23-874

START DATE

12/01/23

END DATE

06/30/24

SPONSORS

Iowa Department of Transportation

Researchers
Principal Investigator
Jonathan Wood

Faculty Affiliate, CTRE

Co-Principal Investigator
Skylar Knickerbocker

Research Scientist, CTRE

About the research

There are three work zone countermeasures with an adequate history of use in Iowa (i.e., end-of-queue warnings, speed feedback signs, and portable rumble strips), and now work zone crash modifications factors (WZCMFs) are desired.

Since the data collection, methodological development, and analysis of all three countermeasures is not feasible within the budget for this project. Instead, the researchers will start by collecting data for and developing WZCMFs and other factors for a single countermeasure (i.e., end-of-queue warnings [most likely, as recommended by the team]). However, the determination of the countermeasure for the main focus will be determined through discussions between the research team and Iowa Department of Transportation (DOT).

While collecting the data for the main countermeasure to be evaluated, data for the other countermeasures will be collected, as available. This will result in preliminary datasets being curated to support the WZCMFs and other metric development for the remaining countermeasures. The analysis will then develop the WZCMFs and other appropriate metrics for the target countermeasure.

Project Details
STATUS

In-Progress

PROJECT NUMBER

23-870

START DATE

11/01/23

END DATE

06/30/25

SPONSORS

Iowa Department of Transportation

Researchers
Principal Investigator
Jonathan Wood

Faculty Affiliate, CTRE

About the research

This project is on the evaluation of the impacts of dynamic speed feedback signs (DSFS) being installed in Iowa at transition zones as posted speed limits are reduced as highways enter towns. The first phase, focusing on the impacts of the signs on traffic operating speeds, will utilize connected vehicle and other data sources to provide data analytics to evaluate the effectiveness of the DSFS in transition zones. Data for all locations being installed in Iowa in 2023 and 2024 (approximately 80 total locations) and 80 similar locations without DSFS will be used in the study. Additionally, crash, traffic volume, and other data for these locations will be collected as part of this phase of the project to support a potential second phase that will focus on evaluating the impacts of DSFS on crashes in transition zones.

Project Details
STATUS

Completed

PROJECT NUMBER

16-579, TR-710

START DATE

07/01/16

END DATE

03/29/24

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC, CTRE
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

Co-Principal Investigator
Alice Alipour

Structure and Infrastructure Engineer, BEC

About the research

The Iowa secondary road system has a large number of scour-susceptible bridges or bridges with unknown foundation conditions. These structures are commonly required to have a plan of action (POA) to close them during flood events, or have countermeasures installed to keep them open. In the case of unknown foundations, countermeasures must be installed.

Among the many different countermeasures available is a potentially viable technique known as a partially grouted revetment. Partially grouted revetment construction involves the placement of rock, stone, and/or recycled concrete on a filter layer that is compatible with the subsoil. The voids of the matrix are then partially filled with a portland cement-based grout material.

Partially grouted revetment appear to achieve a desirable balance between full and no grouting of revetment. Specifically, partial grouting increases the stability of the system without eliminating the flexibility of a looser matrix. In addition, a partially grouted revetment system allows for the use of smaller (and less expensive) rock, stone, and/or recycled concrete, which also results in decreased layer thickness. The ideal system adheres adjoining pieces together while leaving relatively large voids between the stones.

The final project report presents background information on countermeasure types and their frequency of use, including a field review of existing countermeasures to determine quality of performance. These efforts were followed by several pilot installation sites on county infrastructure in Iowa using partially grouted riprap. These pilot installations are described and their performance documented after years of service.

Project Details
STATUS

Completed

PROJECT NUMBER

20-733, TPF-5(438)

START DATE

01/01/21

END DATE

03/08/24

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, SWZDI
SPONSORS

Iowa Department of Transportation
Smart Work Zone Deployment Initiative

Researchers
Principal Investigator
Timothy Gates
Co-Principal Investigator
Peter Savolainen
Co-Principal Investigator
Praveen Edara
Co-Principal Investigator
Henry Brown

About the research

This study investigated methods for improving the effectiveness of speed feedback trailers (SFTs) when used as a speed management strategy in highway work zones. The research included a literature review, a state department of transportation (DOT) survey, and field evaluations conducted at several freeway work zones. The findings were synthesized to provide recommendations on methods for optimizing the deployment of SFT in freeway work zones. The state DOT survey revealed that SFTs are widely implemented in work zones across the United States, most commonly for lane closures and traffic shifts. Their use varies across states, ranging from optional to mandatory under specific conditions. SFTs are most commonly positioned near the work area or in advance of the lane closure taper and are often relocated as the work progresses. From there, a series of field studies were conducted within freeway work zones in Michigan and Missouri to evaluate the effectiveness of various SFT deployment strategies towards reducing work zone speeds and improving speed compliance. These evaluations, conducted in multiple phases and at five freeway work zone locations, sought to yield insights and recommendations for optimizing SFT deployment and introducing measures to improve their overall effectiveness. The evaluations specifically assessed the impact of strategically placing SFTs at various locations within the work zones, including near the start of a lane closure, approaching a work area, approaching a lane shift, and within a freeway crossover. Additionally, the effectiveness of SFTs were also assessed when combined with other strategies, like digital speed limits (DSLs) signs and police vehicle presence within the work zone. Although SFTs were generally effective at reducing work zone speeds regardless of the deployment characteristics, they tended to be more effective when positioned closer to the work area, including ingress/egress locations, where speeds were up to 3.6 mph lower when the SFT was present and active. SFTs were also effective at lowering work zone speeds when positioned within 1,000 beyond the end of the lane closure taper, within 1,000 ft in advance of the start of the taper, and within freeway crossovers. The speed reduction effects were generally sustained for at least one-half mile beyond the SFT. SFTs were also found to improve speed reductions measured near a police vehicle positioned within the lane closure by an additional 1.4 mph. Additionally, when paired with DSL signs on the same trailer assembly, the speed feedback display reduced speeds near the work area by an additional 1.8 mph. It is recommended that if only a single SFT is to be used, it should be positioned near the work area, approximately 200 ft in advance of the active work. If additional SFTs are available, then it is recommended that one be positioned within 1,000 ft upstream of the lane closure, shift, or crossover. Additionally, an SFT should be placed shortly beyond the end (e.g., within 1,000 ft) of any lane closure taper, preferably adjacent to the initial speed limit sign.

Project Details
STATUS

In-Progress

PROJECT NUMBER

24-873, TR-831

START DATE

01/01/24

END DATE

12/31/26

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Zhengyu Liu

Research Engineer, BEC

Co-Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

About the research

State and federal legislators regularly request increases to the axle or gross weight limits for commercial vehicles. The question that is always asked is, “What is the impact on the life expectancy of a bridge when heavier loads are allowed on some vehicles?” There is no past or present method to determine how heavier loads affect the life of Iowa highway bridges. Bridge owners need a method of quantifying the effects of heavier loads or any load on a bridge’s life expectancy. The objective of this research is to qualify the relationship between increased legal loads and reduced bridge service life for Iowa bridges. To achieve the proposed objective, a 36-month research plan was developed, which includes conducting a comprehensive literature review, collecting Iowa-specific data, estimating bridge costs and life reduction due to truck weight limitation increases, and performing the laboratory test for the validation of bridge life reduction prediction. The result of this project will help the bridge owner make reasonable assumptions on the life of a bridge when subjected to increased truck loads.

TOP