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NRC Research Associates Help EAR Program Solve Transportation Issues

Publication Highlights Research Associateship Program Alumni

Research Associates Discuss Their Research at the EAR Program Booth During TRB 

Research Associates Help Advance Critical Research

New NRC Associates Arrive at TFHRC

The Turner-Fairbank Highway Research Center (TFHRC) conducts research across a wide range of topics and disciplines. To supplement the expertise of the permanent staff, it is important to bring in researchers with the appropriate backgrounds to investigate specific problems on a short-term basis. Through the Exploratory Advanced Research (EAR) program, the Federal Highway Administration (FHWA) utilizes the Research Associateship program (RAP) of the National Academy of Sciences (formerly the National Research Council (NRC)) for this purpose. The NRC provides a process for selecting candidates on a competitive merit basis and (subsequently) for administration of the resident fellows during their tenures at FHWA.

Through the RAP program, the EAR program is able to:

  • Provide postdoctoral scientists and engineers of unusual ability and promise an opportunity to conduct research on problems, largely of their personal choice, that are compatible with the research interests of TFHRC.
  • Contribute to the general research efforts of TFHRC.

Associates have worked on topics as diverse as nanoadditives for concrete and asphalt, alternative intersection and interchange design, and modeling to predict collisions based on driver behavior and environmental conditions. A list of current FHWA research opportunities can be found here.

The EAR program's Exploratory Advanced Research Program Research Associates Program 2021 summary document contains descriptions of some of the research projects that the resident fellows have been involved in during their respective tenures at FHWA.

Publication Highlights RAP Alumni

The EAR program publication FHWA Research Associateship Program Highlights: Where Are They Now? provides an overview of RAP and profiles four of the program's alumni who have gone on to work in industry, academia, and government.

RAP provides postdoctoral candidates the opportunity to spend 2 or 3 years working on leading-edge transportation research in world-class facilities with top-notch experts. Research associates are matched with an FHWA adviser who mentors them throughout the program. Since 1992, FHWA has sponsored 50 research associates.

The publication is available here. For more information about the program, contact Jim Shurbutt at 202–493–3420 or

Research Associates Discuss Their Research at the EAR Program Booth During TRB

FHWA's EAR program highlighted the work of 11 of its research associates in its exhibit booth at the Transportation Research Board's (TRB) 99th Annual Meeting in January 2020. Throughout the exhibition, the associates presented their cutting-edge research projects and discussed the program that brought them to FHWA.

Renowned Associate Dr. Mohamed Ahmed's project, "Toward Safer and Efficient Implementation of Automated Driving Systems: Performance Measurements and Evaluation," addresses two problems: (1) that no standards exist for assessing the safety of automated driving systems (ADS); and (2) the effect environmental factors have on ADS performance. His research aims to develop a framework for safety performance measurements and evaluation of ADS and to demonstrate the potential benefits of connected and automated vehicles (CAVs) using experimentation and analysis modeling simulation of driver behavior.

"The evaluation of ADS is not an easy task. When it comes to safety in particular, the assessment is even harder," said Dr. Ahmed. "Traditional safety assessment in the era of ADS must be redefined. Whether to depend on limitations and market readiness of ADS provided by the auto manufacturers; conduct field testing in controlled environments; use disengagements data of automated vehicles (AVs) as a proxy of safety or number of AV crashes on public roads; or use other surrogate measures of safety, such as vehicle miles traveled compared to conventional vehicles, coming up with a framework for fair and doable safety performance evaluation is a key."

"Photograph. A man stands behind a podium with an open laptop and looks at the camera. Behind him is an exhibit display."
Renowned Associate Dr. Mohamed Ahmed at the EAR program booth at the TRB exhibition in January 2020.

Dr. Pavle Bujanovic, a former associate who recently joined the staff of FHWA's Office of Operations Research and Development (R&D), presented his project, "Developing Automated Driving Systems and Predicting Highway-Wide Impacts." He is developing and advancing current vehicle platooning concepts on the CARMA platform and using simulation tools to predict the impact of cooperation-enabled ADS systems on highways.

"Our simulation results indicate that vehicle platooning has the potential to almost double the capacity of our Nation's highways," said Dr. Bujanovic. "To reach these benefits, we are working on improving platooning algorithms so that they use a higher level of coordination between vehicles, making sure that we are getting from our origins to our destinations as safely and efficiently as possible."

Dr. Alireza Mohebbi works in both the structural and concrete laboratories at TFHRC. His project, "Development and Evaluation of Innovative Structural Systems with UHPC and Resilient Connections: From Analyses and Experiments to Design Guidelines," addresses major challenges facing our Nation's crumbling bridge infrastructure.

"Ultra-high performance concrete (UHPC) has been identified as a novel solution that not only can expedite the repair and construction process but also can increase the service life of the bridge elements," said Dr. Mohebbi. "In addition, the structural performance and long-term durability of bridge elements with UHPC far exceeds those of conventional concrete. UHPC provides the opportunity to build long-span bridges with refined cross sections and possibly reduces the number of substructure systems required for multi-span bridges.

"The NRC Research Associateship program has provided me with the opportunity to work with an experienced team at TFHRC to investigate UHPC structural performance and develop design guideline specifications," said Dr. Mohebbi.

Through the EAR program, FHWA participates in RAP by inviting postdoctoral researchers with appropriate backgrounds to investigate specific problems on a short-term basis across a wide range of topics and disciplines. More information about the RAP is available by contacting Jim Shurbutt at 202-493-3420,

Research Associates Help Advance Critical Research

FHWA's EAR program uses the RAP to complement the expertise of permanent research staff on a short-term basis. Associates work with FHWA advisers to conduct important research across a wide range of topics and disciplines. Since 1992, FHWA has sponsored 50 research associates. Two of those associates—Mehdi Zamanipour and Rafic El-Helou—started conducting research at TFHRC in 2016. Their work contributed to advancing research in two important areas: CAV technology and UHPC.

Zamanipour received his Ph.D. from the University of Arizona in industrial engineering, where his research focused on connected vehicle (CV) technology, traffic optimization, and data modeling. He was selected for RAP and began working with his adviser, Govind Vadakpat, in FHWA's Office of Operations R&D on a project titled "Cost-Benefit Analysis of Connected and Automated Vehicle Operations." He then became part of the CARMA team to leverage automated driving technologies to increase safety and reliability. Zamanipour worked on developing optimization models for deploying cooperative automated driving technologies along signalized corridors to support the CARMA platform.

The real-world experiences that he obtained at FHWA gave him valuable exposure to the development of CAV. In January 2020, Zamanipour became a software engineer at an AV technology company.

Photograph. A man looks at the camera while standing next to an SUV. The vehicle has equipment affixed to its roof.


Former research associate Mehdi Zamanipour works with one of the CARMA vehicles at TFHRC.

El-Helou received his doctorate in structural engineering from Virginia Tech. During his time as an associate, he worked under the guidance of Benjamin Graybeal in the FHWA Office of Infrastructure R&D on UHPC-related projects. The goals of these projects were to develop a UHPC bridge-design specification draft for the American Association of State Highway and Transportation Officials (AASHTO) and advance innovative structural applications that fully utilize UHPC's durability and performance characteristics.

The research could encourage simplicity, speed, and creativity in designing and implementing UHPC in the highway system. El-Helou's investigation also provided suggestions on the optimal use of UHPC in innovative highway applications, including extending the span range of concrete bridges beyond the current limit of approximately 200 ft. In addition, El-Helou conducted material-level tests as part of an effort to standardize mechanical testing of UHPC. His work as an associate allowed him to examine different parts of structural design, including material behavior, testing methods, and flexural and shear behaviors of UHPC components.

Photograph of a man in a hard hat using an instrument to take measurements on a concrete beam.

Former research associate Rafic El-Helou installs sensors to measure the deformation of a UHPC beam in FHWA's structures laboratory.

El-Helou concluded his tenure as an associate in October 2019, but he remains at TFHRC as a contractor in the structures lab. "My passion to continue working on UHPC structural guidance prompted me to stay at TFHRC and continue the work I started as an associate," he said.

For more information about the RAP at TFHRC, contact Jim Shurbutt at 202–493–3420 or

New NRC Associates Arrive at TFHRC

Photograph of five research associates standing on stairs.

The NRC Associates from top: Zhou Yang, Milena Rangelov, Mohammad Goli, Heng Liu, and Sattar Dorafshan.

In January 2019, the EAR program welcomed five new NRC Research Associates. The associates and their research projects are:

  • Dr. Sattar Dorafshan – “Networks for Interpretation of Nondestructive Evaluation of Bridges.”
  • Dr. Mohammad Goli – “Design and Implementation of an MPC-Based Framework for Vehicle Platooning.”
  • Dr. Heng Liu – “Artificial Intelligence-Aided Bridge Condition Assessment System Using Deep Learning Approaches.”
  • Dr. Milena Rangelov – “Integrating Life Cycle Thinking into Current Pavement Practices.”
  • Dr. Zhou Yang – “Performance Management Strategy by Integrating Multiple Transportation Data Sets.”
Last updated: Friday, July 22, 2022