Transportation Policy Drives Baker School’s Research in Energy and Environment
For over a decade, the Howard H. Baker Jr. Center for Public Policy conducted energy and environmental policy research, informing policy on issues that were passions for Senator Baker. When the Center became the Howard H. Baker Jr. School of Public Policy and Public Affairs (Baker School) in 2023, the former Energy and Environment Program became the Center for Energy, Transportation, and Environmental Policy (CETEP). Although transportation is a new word in the center’s name, it does not suggest a new direction of research. Instead, it recognizes that CETEP’s energy and environment research also provides critical insights for transportation policy decisions.

A prime example of how research is informing policy is the landmark Valley Pathways Study published by the Baker School and the Tennessee Valley Authority (TVA) in 2023. The study explores ways to achieve net-zero greenhouse gas (GHG) emissions in the Tennessee Valley region by 2050. Electrifying all passenger vehicles and moving to low-carbon fuels for heavy-duty vehicles like trucks, trains, and planes – one of many strategies the study explored – would cut GHG emissions by 90%.
Transportation policy also affects Tennessee’s economy, supply chain, and workforce. CETEP Senior Fellow and Research Professor David Greene spoke this past summer at the Drive Electric Tennessee’s Momentum Summit on the importance of the electric vehicle (EV) industry for Tennessee’s economy, including the benefits of retraining the workforce with the skills needed to manufacture electric vehicles, their batteries, and other parts.
The Intersection of Transportation Policy Research with Energy and Environment
CETEP’s research is accomplished through a network of faculty and affiliates whose research covers many topics. One duo has been responsible for much of the center’s transportation policy research – Greene and Assistant Professor Benjamin Leard. Greene joined the University of Tennessee in 2010 in a joint appointment while still employed at ORNL. He began working on projects with the Baker Center and retained his research professorship and senior fellow position after retiring from ORNL in 2013. Leard joined the University of Tennessee in the department of Agricultural and Resource Economics, serving as a faculty research fellow with the Baker Center from the start. He recently joined the Baker School Faculty with a full-time appointment.
Over the last few years, Greene and Leard have been working on a research project for Oak Ridge National Laboratory (ORNL) that can help policymakers understand how soon electric vehicles (EVs) are likely to make up most vehicles on the road. This information is key to estimating whether the U.S. can meet its goal to cut all GHG emissions from the transportation sector by 2050, using strategies that include a major shift to EVs. According to Greene and Leard, it is not just a matter of manufacturing more EVs. The pair has analyzed the used vehicle market and found that the longevity of cars and light trucks has been increasing for half a century or more. This means that even if an owner decides to trade in an older, gas-powered vehicle, it is now durable enough that it will stay in the used market longer before it is retired and scrapped.

It led Greene and Leard to ask how longer vehicle life affects the market for electric vehicles. Leard, an economist, wanted to explore how subsidizing EV purchases could affect the prices of used vehicles and their longevity. The two researchers developed a model and created a statistical estimation of trends in scrappage and continued survival of light-duty vehicles. They have also begun researching how these factors may vary state by state.
Greene has spent nearly 50 years in the field, including a recent role in which he advised the National Highway Traffic Safety Administration on the CAFE vehicle fuel economy standards. He says the improvement in energy efficiency is the most significant change he has seen in transportation. In 1977, the transportation sector was dependent on petroleum for 90 plus percent of its energy. Although most vehicles today still run on petroleum, there has been an 8% reduction. That might not seem like much, but Greene says the numbers tell an astonishing story. Greene and CETEP Director Charles Sims authored a paper that estimated that 2 trillion gallons of gasoline have been saved by energy efficiency improvements. That is enough to run all the cars and light trucks on the road in the U.S. for 18 years.
Today, Greene has shifted his research focus from petroleum supply to addressing greenhouse gas emissions. Greene says this is the most exciting public policy issue in the transportation sector for the next few years. Transitioning into a zero-emission transportation system is a huge undertaking, and all roads point to electric vehicles, Greene said. This complex transition involves not only vehicles but charging infrastructure, which will once again draw on public policy as a driving force to reach that goal.
Leard is working with CETEP Senior Research Associate Jilleah Welch to build a forecasting model for TVA that will forecast EV registration in Tennessee counties using inputs such as household demographics and vehicle characteristics. This model will be helpful for anticipating the locations of future greenhouse gas emissions and electricity demand in the TVA region.
Balthrop Brings in a New Approach to CETEP’s Transportation Research
CETEP welcomed economist Andrew Balthrop this fall to add another dimension to the center’s transportation research expertise. Balthrop will teach at the Baker School and within the department of Supply Chain Management at the Haslam College of Business. His research focuses on the intersection of freight transportation, supply chain, and public policy.

“Freight policy is comparatively under-studied, at least by economists,” Balthrop said. “But their perspective is needed.”
Supply chain studies consider many issues other than transportation, such as procurement, inventory management, and product design considerations. The transportation-related factors include the cost of moving goods and materials, the effects of sourcing decisions, and where to stage inventory. Each of these factors has impacts on the energy usage and environmental footprint of an industry.
Balthrop is currently measuring the effect of Smartway, an EPA-sponsored voluntary program for reporting heavy truck emissions. The idea behind Smartway is that companies who report the level of emissions caused by their shipments will be motivated to choose clean trucking companies, leading to a virtuous cycle where motor carriers compete not only on providing transport, but also on reducing environmental impact.
He believes that now is a crucial time for both transportation and supply chain research. “Transportation is changing so quickly,” he says. “Automation and electrification are two big trends, but there are so many unanswered questions.”
He also says academic research is important in policy debate because it brings politically neutral results to the table. “When academic policy researchers study something, at least ideally, they only care about the accuracy of their findings, not what the findings actually are.”
Balthrop was hired as part of UT’s Future Mobility Cluster, an initiative to recruit top-tier faculty to collaborate to solve society’s most challenging mobility issues. “Dr. Balthrop’s presence in the cluster allows us to understand the environmental impact of new technologies and the regulatory frameworks that may accompany their rollout,” said Kevin Heaslip, director of the Center for Transportation Research.
Transportation is not a new frontier for CETEP, as it has always played a part in its energy and environment work. The addition of Dr. Balthrop and CETEP’s role in transportation-related research initiatives across the campus reaffirms the critical role transportation plays in energy and environmental policy. Moving into its second decade, the Center will continue to conduct research that improves quality of life for citizens in Tennessee, the U.S., and around the world by exploring the interaction of energy, environmental, and transportation policy.