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 uncertain...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.展开更多
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 "cred...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.展开更多
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,wh...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.展开更多
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）...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.展开更多
基金Project(BX20180268)supported by National Postdoctoral Program for Innovative Talent,ChinaProject(300102228101)supported by Fundamental Research Funds for the Central Universities of China+1 种基金Project(51578150)supported by the National Natural Science Foundation of ChinaProject(18YJCZH130)supported by the Humanities and Social Science Project of Chinese Ministry of Education
文摘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.
基金supported by the National Natural Science Foundation of China (Project No.51608455)
文摘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.
基金Supported by the National Natural Science Foundation of China(71231007)
文摘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.
文摘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.
