Research on optimization model of differentiated toll rate of expressway towards sustainable transportation development

To explore the basis and implementation effects of differential toll rate formulation for expressways, reduce the financial burden of expressway operators, and scientifically guide traffic flow, this study proposes an expressway differential toll rate optimization model. The model is demonstrated using two pilot sections of G25 and G1112 expressways in J province of China, where differential tolling is implemented. Based on the change characteristics of traffic flow and toll amount of the two pilot sections before and after differential tolling, we propose an optimization model of differential toll rate for expressways that maximizes the net revenue of expressway operators while minimizing individual travel impedance. The optimization model is solved using MATLAB, and an optimal differential toll rate scheme by road section, time period, and vehicle type is obtained. The evaluation of the model is based on the net revenue of highway operators and individual travel impedance. The findings reveal that the proposed optimal rate scheme improves the net revenue of road operators while reducing individual travel impedance compared to the original toll rate scheme. Specifically, the differential toll pilot sections of G25 and G1112 can increase net revenue by approximately Rmb25,000,000 and Rmb16,000,000 per month, respectively, and reduce vehicle travel impedance by about Rmb37 and Rmb32 per vehicle. The proposed model balances highway operator revenue with individual travel costs, leading to more sustainable and efficient expressway use, which benefits expressway transportation sustainability.