ICT Develops Ideal Framework for Automated and Connected Truck Platooning

Researchers at ICT are working to improve safety and save money for the traveling public by developing what they believe is the ideal framework for automated and connected truck (ACT) platooning.

A 3D rendering image of a fleet of self-driving trucks platooning on a highway.

Truck platooning is defined as a convoy of trucks traveling at a very close distance. The introduction of ACTs in freight transportation is expected to bring many advantages. Among them, addressing the limitations and risks associated with having humans as drivers. Truck drivers in the U.S. are currently not allowed to work more than 11 hours per day and 60 hours per week. This restriction can be relaxed even with a limited level of automation; e.g., level 4, where the presence of a human is required within a truck. Ideally, under the assumption of full automation, the operation time can even be extended to 24 hours, which could significantly improve the efficiency of freight transportation and lower costs.

Truck platooning is expected to reduce congestion, braking, and accelerating as well as improve safety, traffic flow, and fuel efficiency. With the intelligent technologies used in ACTs that enable connection among vehicles and between vehicles and infrastructure, truck platooning is expected to be more efficient and feasible. In fact, it has the potential to eventually be the main mode of moving goods by trucks on interstate highways in the next decade.

(a) No lateral shifting

(b) Laterally shifted trucks

Figure 1: Aerodynamic drag modelling of platooning truck

One of the main driving motivations behind the development of truck platooning is the reduction of fuel consumption and emissions. These benefits are realized by positioning the trucks one after another to reduce the aerodynamic drag on them. Most of the aerodynamic drag (70 to 90%) is caused by the pressure difference between the front (high-pressure zone) and rear (low-pressure zone) of a truck, known as the pressure drag. In a platoon, the pressure drag on trailing trucks decreases since the trucks in front of them block the air which lowers the frontal high-pressure zone. For leading trucks, aerodynamic drag also decreases because the trailing truck compresses the turbulent flow that increases the pressure in the low-pressure zone (Figure 1). This results in significant fuel savings that benefit the trucking operation. However, such platooning operations may accelerate the damage accumulation in pavement structures. This accumulated damage is a result of the channelized traffic, which is more scattered for human-driven trucks (Figure 2).

The ICT team (consisting of Professors Imad Al-Qadi and Yanfeng Ouyang and graduate students Erman Gungor and Ruifeng She) has developed an optimization framework that generates optimum platooning skeletons (i.e., the lateral configuration of ACTs in a platoon) for any platoon size. Results showed that the total cost, summation of fleet operational costs, and pavement maintenance and rehabilitation costs could be reduced by $500,000 per mile, per year on average over 45 years of the analysis period assuming 100% ACT penetration.

“Our aim is to develop a methodology that can save fuel, minimize emission, and reduce trucking operation cost, while also increasing the pavement system life,” Al-Qadi said. “The research outcome will further allow the design of pavement to explicitly consider the lateral position of truck loading. This will allow us to be better prepared for budget allocation strategies for the roadway infrastructure.”

Figure 2: Developed optimization framework

“The next step is to extend this work from a freight corridor to a complete freight logistics network, where various pavement sections, material characteristics, and different climatic conditions will be considered,” Ouyang said.

Freight facility deployment, shipment routing at both network and corridor level, truck weight loading under general traffic equilibrium, as well as life-cycle pavement design and management, will be addressed holistically to improve efficiency and sustainability.

The research team will focus on validating the results of this research by designing and conducting field experiments; such as the one being planned at the University of Illinois Urbana-Champaign (UIUC) under the Smart Transportation Infrastructure Initiative (STII). The work on platooning is supported in part by the CCAT Center, the University Transportation Center for Region 5, which is funded by the United States Department of Transportation’s Office of the Assistant Secretary for Research and Technology (OST–R) through the University of Michigan.