Traffic assignment problem under tradable credit scheme in a bi-modal stochastic transportation network: A cumulative prospect theory approach

The traffic equilibrium assignment problem under tradable credit scheme(TCS) in a bi-modal stochastic transportation network is investigated in this paper. To describe traveler’s risk-taking behaviors under uncertainty, the cumulative prospect theory(CPT) is adopted. Travelers are assumed to choose the paths with the minimum perceived generalized path costs, consisting of time prospect value(PV) and monetary cost. At equilibrium with a given TCS, the endogenous reference points and credit price remain constant, and are consistent with the equilibrium flow pattern and the corresponding travel time distributions of road sub-network. To describe such an equilibrium state, the CPT-based stochastic user equilibrium(SUE) conditions can be formulated under TCS. An equivalent variational inequality(VI) model embedding a parameterized fixed point(FP) model is then established, with its properties analyzed theoretically. A heuristic solution algorithm is developed to solve the model, which contains two-layer iterations. The outer iteration is a bisection-based contraction method to find the equilibrium credit price, and the inner iteration is essentially the method of successive averages(MSA) to determine the corresponding CPT-based SUE network flow pattern. Numerical experiments are provided to validate the model and algorithm.

Does driving-day-based tradable credit scheme outperform license plate rationing? Examination considering transaction cost

This article models a novel driving-day-based tradable credit scheme (DD-TCS) to alleviate urban traffic congestion. In this model, car-using allowances (in terms of the number of days in a month, termed as "credit") are freely and uniformly allocated to all travellers, who are also allowed to trade them in a market according to his/her travel needs (e.g. driving more or fewer days than the free endowment). As opposed to most studies on TCS, this paper explicitly considers the transaction cost (e.g. infor-mation cost of finding potential traders) in the trading market. To assess the feasibility of DD-TCS, we compare it against the license plate rationing (LPR) scheme, which has been practically implemented in many cities such as Beijing and Chengdu in China. Taking the performance of LPR as a benchmark, we quantify the threshold values of the transaction cost in DD-TCS when the two schemes yield equivalent performance (in terms of the total gener-alized cost). In numerical studies, we also compare the DD-TCS and LPR with the no-action case and the congestion pricing case (representing the theoretical optimum). Results show that both DD-TCS and LPR outperform the no-action case under certain conditions. With small trans-action cost, DD-TCS may achieve a lower system cost that can be very close to the ideal optimum. In addition, parameter analysis shows that DD-TCS performs better than LPR in a wide range of transaction cost, where the threshold values appear to account for a considerable portion of the auto travel time. This implies that DD-TCS will be more appealing than LPR in practice because a transaction cost lower than the extremely large threshold values can be easily achieved for the trading market, e.g. via a mobile platform and modern communication techniques.

Effects of herding behavior of tradable green certificate market players on market efficiency:insights from heterogeneous agent model

Tradable green certificate(TGC)scheme promotes the development of renewable energy industry which currently has a dual effect on economy and environment.TGC market efficiency is reflected in stimulating renewable energy investment,but may be reduced by the herding behavior of market players.This paper proposes and simulates an artificial TGC market model which contains heterogeneous agents,communication structure,and regulatory rules to explore the characteristics of herding behavior and its effects on market efficiency.The results show that the evolution of herding behavior reduces information asymmetry and improves market efficiency,especially when the borrowing is allowed.In addition,the fundamental strategy is diffused by herding evolution,but TGC market efficiency may be remarkably reduced by herding with borrowing mechanism.Moreover,the herding behavior may evolve to an equilibrium where the revenue of market players is comparable,thus the fairness in TGC market is improved.

How will tradable green certificates affect electricity trading markets under renewable portfolio standards?A China perspective

Renewable portfolio standards(RPS)are important guarantees to promote renewable energy(RE)consumption.The tradable green certificate(TGC)trading mechanism is a supporting mechanism of RPS,but the rate of TGC trading is low and there is a double-metering problem of RE consumption.With the introduction of new policies in China,we innovatively take the electricity-selling side as the subject of RE consumption responsibility and biomass-based electricity-generation(BEG)projects are considered to participate in TGC trading.To explore the interaction between the TGC market and the electricity market,this paper sets up a day-ahead spot market-trading structure combining both markets under RPS and establishes a market equilibrium model.The established model is solved and validated based on the particle swarm optimization algorithm and the profits of each market player under different influencing factors are analysed.The main conclusions are as follows.(i)The established market structure and model effectively solve the double-metering problem of RE consumption,making the TGC turnover rate reach 82.97%,greatly improving the market efficiency.(ii)Increased demand for TGC will increase demand for RE electricity.The participation of BEG projects in the TGC market can effectively improve the profit of biomass-based electricity producers(BEPs),reduce the burden of government financial subsidies and will not affect the consumption of wind-based electricity and photovoltaic-based electricity.This will help promote the rapid development of China’s RE,especially the BEG industry.(iii)Among the influencing factors,the increase in renewable-energy consumption responsibility weight and the decrease in electricity-generation cost can increase the profit of BEPs.The decline in TGC price and subsidy price will reduce the profit of BEPs.Finally,we put forward policy recommendations for China’s RPS and TGC trading mechanism.This study can provide a reference for the construction of China’s TGC market and electricity market and the development of RE.

Alternative Tradable Credit Scheme on General Transportation Network

This paper designs and analyzes an alternative tradable travel credit scheme on general transportation network for managing travelers’route choice behaviors.The scheme is a kind of charging and rewarding mechanism,which provides an attempt to urge travelers to plan their travel routes reasonably so that excessive traffic congestion can be mitigated.Mobility credits are imposed on those travelers who use high congested routes,while rewarded credits are given to those travelers who switch to the low congested routes.A free tradable market is created such that the travelers paying credits can purchase them from those earning them from the rewarding travel route choices.When the total amount of credits earned is equal to the amount of credits consumed,transfer of wealth can only take place among the travelers and hence overcome the inequity problem of congestion pricing.On the general transportation network,the type of tradable credit schemes can be formulated as a mathematical programming with equilibrium constraint（MPEC）model.Based on the model,a credit charging mechanism is obtained under the system optimum and Pareto-improving system optimum conditions.

A modern congestion pricing policy for urban traffic:subsidy plus toll

Congestion pricing is seen as an effective policy to address traffic congestion. In such policies where money, people and authorities are involved, the success generally hinges upon two factors： equity （being fair） and accept- ability （to both people and authorities）. The primary con- cern is the equity, for which ＂tradable credit scheme （TCS）＂ has been introduced and extensively studied in the literature. Nevertheless, due to the com- plexity of the trading schemes, the TCS has yet to find any foot in the real world. To this end, a novel idea of rewarding has substituted the trading component to be known as toll-and-subsidy scheme （TSS）. The idea is to charge the drivers on some roads （toll） while rewarding them to use other alternative--and perhaps underutilized-- roads （subsidy）. The research of the TSS is in its infancy stage. The problem to be tackled in this study is as follows： Given a set of roads constituting a cordon line around the central business district （CBD） or across a screen line, how much toll or subsidy should be assigned to each road？ The problem is first transformed into a capacitated traffic assignment problem. We employ a solution method based on augmenting the travel time of roads up to the level at which the traffic volumes do not exceed some target rates. A real dataset from the city of Winnipeg, Canada, is used as a pilot study. We then discuss policy-related applications of the TSS. It is proved in the literature that one can obtainoptimal TSSs for various objectives and considerations. To this end, the non-negativity of the toll values is relaxed which results in a valid toll set. Nevertheless, the compu- tational time is found to be of highest significance. Our method differs in the fact that the traffic volumes are bounded from the above and it is quite affordable. The main contribution is first to highlight the concept of sub- sidy along with traditional thought of merely toll. Second is to interpret the Lagrangian values of the capacity con- straints as the values of the toll/subsidy.