Transforming Arizona’s highways with innovative solutions

ASU collaborates with Arizona Transportation Institute for durable roads, economic growth and workforce development

Imagine you’re driving down a smooth stretch of road. Your tires have firm traction. There are no potholes you need to swerve to avoid. Your suspension feels responsive. You’re relaxed and focused on your drive.

Arizona drivers will experience that more often on roads that last longer and need fewer repairs thanks to Arizona State University researchers’ innovative transportation solutions developed from five new projects they are leading in the Arizona Transportation Institute, or AZTI.

Hasan Ozer, associate director of the Arizona Transportation Institute and a Fulton Schools associate professor of civil environmental and sustainable engineering.

The projects will assess impacts and costs of heavier vehicles on roads and bridges, provide real-time drive times, manage roadside plants to reduce wildfire risk, find pavement mixes that make roads more durable, and use best practices to manage Arizona Department of Transportation, or ADOT, projects.

“The Arizona Transportation Institute will catalyze research and innovation in the state to build safe, sustainable and durable transportation infrastructure,” says Hasan Ozer, associate director of AZTI and an associate professor of civil, environmental and sustainable engineering in the School of Sustainable Engineering and the Built Environment, part of the Ira A. Fulton Schools of Engineering at ASU.

More than 100 researchers at ASU, University of Arizona and Northern Arizona University are part of AZTI’s collaborative effort with ADOT, local agencies and the U.S. Department of Transportation Federal Highway Administration to support economic growth and workforce development. AZTI is a new transportation institute modeled after similar initiatives in other states.

“Our research is designed to produce actionable insights that can be directly applied to improve infrastructure resilience, sustainability and safety,” says Daoqin Tong, a professor in the ASU School of Geographical Sciences and Urban Planning. “The collaboration with transportation agencies also makes this research particularly impactful.”

Determining vehicle impact costs

In one project Ozer is working on, the team will identify the current impact on Arizona’s roads and bridges of heavier, over-dimension vehicles compared with passenger and commercial vehicles.

Then the team — which includes Kamil Kaloush, FORTA Professor of Pavement Engineering, Angeli Jayme, an assistant professor of civil, environmental and sustainable engineering, project lead Alyssa Ryan, an assistant professor in the Department of Civil and Architectural Engineering and Mechanics at U of A, and Julie McIlwain, senior research project manager for ADOT — will determine the costs to build, maintain and repair Arizona’s roads and bridges for each vehicle category.

Angeli Jayme, an assistant professor of assistant professor of civil, environmental and sustainable engineering.

This project, “Assessing the Consumption Costs of Motor Vehicles on Arizona Roads and Bridges,” is critically important. Electric vehicles, which are heavier than traditional gasoline-powered vehicles due to the weight of their batteries, are increasingly using Arizona’s transportation infrastructure, yet the state’s fuel tax rate for road maintenance is among the 10 lowest in the nation.

The last increase in Arizona’s fuel taxes — the primary source of funding for ADOT to build, operate and maintain roads and bridges in the state highway system — was 18 cents a gallon on gasoline and 26 cents a gallon on diesel in 1991.

“Alternative fee structures are sorely needed to close the revenue gap to maintain Arizona’s transportation infrastructure including roads and bridges,” Ozer says. “By properly assessing consumption costs of pavements and bridges due to motor vehicles, the research team will provide actionable insights that can inform policy decisions and infrastructure planning.”

Real-time traffic conditions model

Updating the current static traffic model to reflect real-world traffic conditions is the focus of a team led by Xuesong Zhou, a Fulton Schools professor of civil, environmental and sustainable engineering, specializing in transportation systems.

Xuesong Zhou, a Fulton Schools professor of civil, environmental and sustainable engineering specializing in transportation systems.

Zhou will work closely with ADOT Senior Research Project Manager David Proffitt to integrate a dynamic step into the existing static traffic model to better represent fluctuating traffic conditions and enhance ADOT’s ability to evaluate complex modernization projects as part of the “Expanding the Capability of Arizona’s Statewide Travel Demand Model Using Dynamic Traffic Assignment” project.

The current model represents average daily traffic conditions between origins and destinations; however, real-world traffic conditions vary significantly within each day. This project will enable more accurate travel forecasts, which will help leaders determine which projects to prioritize and track how well transportation corridors are performing over time.

Managing plants to reduce wildfire risk

Another project will evaluate whether ADOT’s roadside vegetation management practices support the recovery of native plants after wildfires. Researchers will also assess whether these practices can improve ecosystem resilience and reduce roadway repair needs, ongoing maintenance costs, and future wildfire risk.

Tong whose research focuses on spatial analytics, geographic information systems and big data, will work with Proffitt on this “Enhancing Arizona Roadways’ Resilience to Wildfire Through Vegetation Recovery” study.

Daoqin Tong, a professor in the School of Geographical Sciences and Urban Planning at ASU.

“Wildfires pose a growing threat to Arizona’s transportation infrastructure, impacting roadway stability and safety,” Tong says. “Our study integrates field research, remote sensing and geospatial data analytics to assess post-wildfire vegetation recovery and identify optimal restoration strategies.”

Wildfires can cause long-term damage to roadways through erosion and debris flows, which can be made more severe by the slow recovery of native plants. The presence of highly flammable invasive plants increases future wildfire risk and management costs. By partnering with land management agencies, ADOT seeks to improve wildfire resilience and establish effective post-wildfire maintenance practices.

“This project leverages geospatial analysis and remote sensing technologies to assess post-fire vegetation recovery patterns,” Tong says. “By integrating these tools with transportation planning, we aim to inform policy decisions and optimize roadside management efforts statewide.”

Asphalt mixes that reduce repairs

Kaloush leads work with Ozer and McIlwain on resilient pavements that reduce road repairs as part of the “Assessment of Asphalt Shear Rutting Test Method to Improve the Performance of ADOT Asphalt Mixes” research study.

Kamil Kaloush, FORTA Professor of Pavement Engineering in the School of Sustainable Engineering and the Built Environment at ASU.

Kaloush says Arizona’s diverse climate presents challenges in balancing asphalt mix performance for cracking and rut resistance. Ruts are the depressions or grooves formed on a road’s surface that are caused by vehicles’ wheel paths over time.  The use of various modifiers further complicates pavement mix stiffness and long-term performance.

“Selecting an appropriate rutting test is crucial for implementing a balanced mix design, or BMD, framework,” Kaloush says. “Existing tests are time-consuming and costly for routine industry quality control and assurance. ADOT is interested in evaluating the IDEAL rutting test due to its simplicity and as a cost-effective alternative; however, further validation and benchmarking is needed.”

The ASU research team is addressing this need by evaluating the test across different climates and traffic conditions in Arizona, collecting field asphalt mixtures and materials from ongoing roadway construction jobs, conducting laboratory rutting experiments and correlating rutting testing protocols with mix performance, Kaloush says.

“Developing or adopting a robust rutting test protocol capable of evaluating the different job mixes produced state-wide and efficiently predicting the mix performance in the quality control/quality assurance stage will be instrumental to the balanced mix design framework,” Kaloush says.

Best practices for tracking resources

The project evaluating how other state departments of transportation manage their project databases to identify best practices for technology, policies and staffing is led by Kenn Sullivan, a Fulton Schools professor of civil, environmental and sustainable engineering.

Kenn Sullivan, a Fulton Schools professor civil, environmental and sustainable engineering.

“This project is focused on enhancing financial tracking systems by analyzing regulatory requirements, evaluating ADOT’s current system and identifying innovative practices from other state departments of transportation,” Sullivan says. “This research integrates multiple systems, including federal and state financial tracking regulations, database structures and system user interfaces.”

Sullivan is working with Proffitt and ADOT’s Financial Management Services Resource Administration team to help ADOT find a permanent solution to issues with their current database used to manage more than $1 billion annually in federally funded projects as part of the “Best Practices for Structuring and Managing Statewide Resource-Tracking Databases” project.

“Our approach ensures that ADOT can make data-driven improvements, aligning with federal and state regulations while incorporating proven, high-performing solutions from other transportation agencies,” Sullivan says. “The research doesn’t just identify problems — it delivers clear, structured recommendations for improving financial management while balancing user-friendliness, scalability and system longevity.”

AZTI: From bold beginnings to what’s next

ADOT hosted a ceremony in Phoenix in the fall to celebrate the partnership where leaders of the three universities and ADOT signed a letter of understanding. The event followed the conclusion of the 21st Annual Arizona Pavements and Materials Conference, which was held on ASU’s Tempe campus.

Ram Pendyala (left), a professor of civil, environmental and sustainable engineering in the Ira A. Fulton Schools of Engineering at Arizona State University and director of the School of Sustainable Engineering and the Built Environment, part of the Fulton Schools, and Kyle Squires (right), dean of the Fulton Schools and ASU senior vice provost of engineering, computing and technology, pose for a photo at the Arizona Transportation Institute signing ceremony to celebrate the partnership held at ADOT headquarters in Phoenix. Photo: Kohinoor Kar/ADOT Research Center

Since the summer of 2024, researchers have collaborated on eight AZTI projects with an estimated economic impact of $3 million each year. ADOT has committed $6.5 million in fiscal year 2024 funding, an additional $2.5 million in fiscal year 2025 and $2.5 million in fiscal year 2026 pending future work program approval. The possible funding opportunities during this period total $11.5 million.

Yao-Jan Wu, executive director of the Arizona Transportation Institute and a professor of civil engineering at the University of Arizona.

AZTI is led by Executive Director Yao-Jan Wu, a professor of civil engineering at the University of Arizona, where AZTI is based.

“It is very exciting to collaborate with talented colleagues and students from three state universities to develop and implement cutting-edge, innovative transportation technologies, planning methods and engineering approaches to improve Arizona’s transportation system and facilities to create better communities,” Wu says.

On March 8, 2025, AZTI’s second round of research idea submissions closed. These next ideas will be ranked and prioritized based on impact, feasibility and alignment with strategic goals. Decisions will then be made to focus on the most promising ideas.

“We’re tremendously excited to partner with talented faculty and students in a way that can improve the lives of Arizonans, support our state’s economy and promote transportation engineering as an exciting and essential career,” says ADOT Director Jennifer Toth.

“This collaboration between ADOT and researchers at the state’s three public universities is exciting and will lead to a transformative change in the transportation engineering field in Arizona,” says Ram Pendyala, professor and director of the School of Sustainable Engineering and the Built Environment. “ASU faculty members and students who focus on transportation will benefit from AZTI by collaborating with colleagues around the state as they conduct their research. I commend Dr. Ozer and the entire leadership team for their vision and hard work that has led to the establishment of AZTI.”