For the last two years, Colorado State University has worked with a group of partners to enable mobility and energy efficiency improvements through a combination of infrastructure-level and vehicle-level control to solve real-world transportation problems in local municipalities. This energy and mobility project, led by Dr. Thomas Bradley, Department Head of Systems Engineering at CSU, studied how to reduce travel time while minimizing energy consumption and human health issues from transportation-related emissions exposure.
“Many vehicles now have real-time connections to infrastructure,” Bradley said. “The question this research asks is if there is a way to use those pieces of data to improve fuel economy.”
This study addressed several problems currently facing the Fort Collins municipality, including traffic congestion, bus rapid transit (BRT) interface at intersections and Class 8 truck transport through town. The project sought to solve these issues by optimizing traffic management systems (TMS) and connected and automated vehicle (CAV) energy management systems (EMS).
By conducting research locally, this study exemplified technologies that enable the use of innovative data and actionable techniques to solve common, modern transportation problems throughout the U.S.
The Mobility & Energy Improvements project required the development and integration of four key technologies and their associated and supporting datasets – optimal traffic management strategy (Optimal TMS), optimal energy management strategy (Optimal EMS), vehicle class-specific models of fuel economy and emissions and novel models and metrics to quantify the broad impacts of prediction-based vehicle powertrain control and traffic management.
CSU began their research by using vehicle probe data collection techniques to gather vehicle class-specific energy consumption and emissions data along all key routes in Fort Collins. This data was then used to validate microscopic traffic simulations to model two artery networks in Fort Collins – Harmony Road, College Avenue and Mason Street. The simulations were tested across multiple metrics of performance, including temporal dynamics, segment speeds, and travel times, to optimize TMS. Vehicle-level EMS optimization was performed by modeling future vehicle operation and controlling the CAV powertrain, which is advantageous because it does not require a change in driver behavior.
A mobility metric called the Mobility Energy Productivity (MEP) metric was developed in collaboration with the National Renewable Energy Laboratory (NREL) to quantify the tradeoffs between energy consumption and mobility for this project.
The MEP focuses on developing integrated transportation systems that maximize mobility while not using too much energy, and the MEP score is calculated by analyzing components of travel time, cost of travel and energy consumption in a given area.
“Something we didn’t expect was the availability of CAVs,” Bradley said. “When we started the project, we weren’t thinking about longitudinal autonomy, where the vehicle can control itself, we were thinking of hybrid-EV powertrain control. We didn’t anticipate these vehicles to be as reliable as they are today, but as we build more CAV capabilities, our ability to use these kinds of tools to realize fuel economy gains will continue to grow.”
This project has been ongoing for the past two years and has only a few months until its completion. Finalized conclusions of the project are still in progress, but there are still several important findings from the study that have emerged.
For example, this study found that throughput on the major artery networks of Fort Collins can be mildly improved, on the order of one to two percent, through rigorous Signal Phase and Timing (SPaT) optimization.
Additionally, it was determined that various optimization schemes for vehicle-level energy management realized a two to four percent improvement in fuel economy.
Although a couple of percentage points do not sound like a significant improvement, the value of thinking about mobility and energy improvements is that many cities, including Fort Collins, have climate action plans in which they try to build up their capability to reduce emissions and invest in clean energy.
If cities could improve the fuel economy of vehicles moving through traffic networks, even by a small amount, they can allocate those benefits to their climate goals.
“Even if we improve fuel economy by only 5%, since transportation is responsible for a third of greenhouse gases in any city, that couple percent is measurable in a climate action plan,” Bradley said.
CSU hopes to be able to share this data with other municipalities with the help of Clean Cities coalitions and evaluate the scalability and replicability of TMS/EMS in the city and county of Denver and beyond.
They are continuing to work with vehicle manufacturers to implement the tools they’ve been developing on the basis of this study and integrate them into actual vehicles on the road.
For more information about this project please join Denver Metro Clean Cities on May 20, 2021, for the Connected & Autonomous Vehicles Energy & Mobility Improvements webinar. Hear from Dr. Thomas Bradley from CSU and Tyler Svitak from the Colorado Smart Cities Alliance about the project research and new initiatives focused on testing these technologies in Colorado.
Stay for an interactive discussion focused on the challenges and opportunities for greater deployment in the state and a chance to engage with smart mobility leaders.