Charge up: Reducing carbon footprint of commercial vehicles

The rise of e-commerce has led to a rapid increase in emissions from medium- and heavy-duty commercial trucks, with emissions rising 78% between 1990 and 2021, according to the U.S. Environmental Protection Agency.

Illinois Center for Transportation and Illinois Department of Transportation aim to reduce emissions in Illinois in the joint project, R27-239: Development of Commercial Vehicle Emission Inventory and Analysis.

Jane Lin, University of Illinois Chicago professor, leads the project with Christopher Schmidt, IDOT’s air quality manager.

“Commercial vehicles and medium- and heavy-duty vehicles are increasingly becoming the main sources of vehicle emissions with the increase of truck traffic,” Lin said. “On a per-vehicle basis they’re much, much more polluting than passenger vehicles. You’re talking about 10, sometimes even 20, times higher on a per-vehicle basis and even a per-mile basis.”

“This is really the nut we have to crack in order to control vehicle emissions and to reduce greenhouse gas emissions,” she added.

The team’s goal is to get a better understanding of commercial vehicle emissions in Illinois and investigate strategies to control those emissions.

Lin’s team used public data from three state and national databases to quantify commercial vehicle emissions by county and identify contributing factors behind high emissions.

They used the EPA’s MOVES model (motor vehicle emission simulator) to calculate emissions per county by pollutant, using 2019 and 2021 data.

A key finding is that the overall average annual daily truck traffic in three major metropolitan areas in Illinois decreased between 2019 and 2021 while the percentage of AADT went up.

This finding indicates that local and regional truck trips increased while longer distance truck trips went down, resulting in an overall decrease in emissions in major pollutants other than methane statewide from 2019 to 2021.

Lin’s team also identified key contributing factors to emissions, including vehicle type, make, age, odometer mileage, fuel type, engine brand and engine built year.

Another key focus involved exploring potential strategies to control emissions in commercial vehicles — particularly the electrification of trucks.

Barriers to the adoption of e-trucks include insufficient charging infrastructure, high initial adoption cost and long charging time due to battery size.

To help overcome these barriers, Lin’s team built a model that identifies the optimum route and driver schedule to minimize operating costs.

Their model tests four e-truck routes on Illinois’ highway system, with paths as short as St. Louis to Chicago to as long as Los Angeles to New York.

It calculates the ideal locations of charging stations, taking into consideration charging times, potential wait times and federally mandated breaks for drivers.

“The idea for this model is to try to minimize this impact of long charging time on the overall operation, because if the driver has to wait long to charge, it’s a disincentive for the driver,” Lin said.

They found that long-haul e-trucks provide over 43% energy savings from diesel trucks, but that high initial costs and prolonged journey time remain barriers to adoption.

“When we are pushing toward electrification, we need to keep in mind how we can devise some really meaningful incentives for truck drivers so that they can be more willing to adopt e-trucks,” Lin said. “The government has to come up with incentive programs to really subsidize this initial transition from the diesel fleet to the electric fleet.”

Lin’s research group is working to expand the research to the entire national highway network, allowing them to investigate wider-scale routes with multiple origins and destinations.

“I want to thank ICT for this opportunity,” Lin said. “Even though the project has officially ended, we’re still continuing to work on the idea.”