Assessing environmental impacts of ad-hoc truck platooning on multilane freeways

Abstract

Truck platooning is an application of connected and automated vehicle technology that has a near-term potential to revolutionize the trucking industry. In addition to potential operational improvements in capacity and flow, its primary benefits include potential reductions in fuel consumption and emissions. In a real-world environment, there are many factors that can influence the ability to form stable and uninterrupted platoons as well as maintain tight platoon spacing. These, in turn, affect the emission benefits of truck platooning. This study developed a mechanism to evaluate truck platooning’s impact on emissions under different scenarios. We modeled truck platooning in VISSIM; a microscopic simulation software and estimated emission rates from second-by-second trajectory data. We used this simulation to evaluate the environmental impact of truck platooning with respect to volume, market penetration rate (MPR) of equipped vehicles, gap setting for platoons, wireless communication quality, and lane use restriction policy. MOVES2014 emission model was used to estimate the emission rates from the vehicle trajectory data with adjusted wind drag coefficients for close spacing during platooning. The results showed that the gap setting of platoons is an important parameter in reducing the emissions where smaller gaps resulted in longer platoons and higher emission reductions. A lane use restriction policy where a platoon is only allowed on the left lane also improves emission benefits because it helps promote platoon formation especially at a low MPR of equipped vehicles.