Generalized link cost function and network design for dedicated truck platoon lanes to improve energy, pavement sustainability and traffic efficiency

Recent development on autonomous and connected trucks (ACT) has provided the freight industry with the new option of using truck platooning to improve their fuel efficiency, traffic throughput, and safety. However, closely spaced and longitudinally aligned trucks impose frequent and concentrated loading on pavements, which often accelerates pavement deterioration and increase the life-cycle costs for the highway agency. Also, effectiveness of truck platooning can only be maximized in dedicated lanes, and its benefits and costs need to be properly balanced between stakeholders. This paper proposes a network design model to optimize (i) placement of dedicated truck platoon lanes and toll price in a highway network, (ii) pooling and routing of ACT traffic from multiple origins and destinations to utilize these lanes, and (iii) configuration of truck platoons within these lanes (e.g., lateral displacements and vehicle separations). The problem is formulated as an integrated bi-level optimization model. The upper level makes decisions on converting existing highway lanes into dedicated platoon lanes, as well as setting user fees. The lower level decisions are made by independent shippers regarding the choice of routes, use of platoon lanes vs. regular lanes, and they collectively determine truck traffic in all lanes. Link cost functions for platoon lanes are obtained by simultaneously optimizing, through dynamic programming, pavement rehabilitation activities and platoon configuration in the pavement's life cycle. A numerical case study is used to demonstrate the applicability and performance of the proposed model framework over the Illinois freeway system. It is shown that the freight traffic is effectively channelized on a few corridors of platoon lanes and, by setting proper user fees to cover pavement rehabilitation costs, system-wide improvements for both freight shippers and highway agencies can be achieved.