A Fundamental Analysis of the Impact on Traffic Assignment by Toll System of Electric Road System
Wataru Nakanishi, Noriko Kaneko
TL;DR
This paper addresses how toll policies on an Electric Road System (ERS) influence traffic assignment when DWPT-enabled EVs and conventional vehicles share a simple network. It develops a deterministic user-equilibrium framework under two toll schemes (toll-free and fixed-toll) and two formulations for charging utilities, then analyzes how outcomes such as total travel time ($TTT$), total charged volume ($TCV$), and ERS utilisation depend on the DWPT-ratio $r$, EV state-of-charge distributions $s_i$, VoE, and toll price $C$. The results show that toll design can fail to achieve social optimality or fully exploit ERS, with pronounced sensitivity to $r$, battery levels, and electricity pricing dynamics, underscoring the need to integrate charging behavior into toll policy. The study suggests extending to larger networks and exploring additional toll structures as well as improvements to the charging utility model to inform ERS deployment decisions.
Abstract
Electric road system (ERS) is expected to make electric vehicles (EVs) more popular as EVs with Dynamic Wireless Power Transfer (DWPT) system can be charged while driving on ERS. Although some studies dealt with ERS implementation, its toll system has not been explored yet. This paper aims at a fundamental analysis on impact of ERS toll system on a traffic assignment. We conduct assignments on a simple network where two vehicle types (EVs with DWPT and others) are co-existing. The results under two toll systems showed some undesirable situations, such as total travel time was not minimised, total charged volume was not optimised, and ERS was not utilised. The occurrence of them depended on the ratio of EVs, battery level, value of electricity, and toll price. The difficulty to control such situations by toll price was discussed as the battery level and value of electricity may vary over time.