Modeling And Analysis Of Tradable Credit Scheme Considering Equity Effects

As an effective alternative to congestion pricing,tradeable credit scheme has been widely studied by scholars at home and abroad.On the basis of tradable credit mechanism,although different individuals have different travel choice behaviors under the tradeable credit scheme,all of them can get more benefits compared with congestion pricing.Therefore,tradeable credit scheme can obtain higher public support,but there are still exist some equity problems.From the perspective of behavioral economics,travelers in the transportation network which implementing the tradable credit scheme not only consider the time cost and the credit cards cost when selecting path,but also consider the psychological effects difference caused by buying or selling credit cards.So that traveler's path choice behavior is different from the road traffic congestion pricing scheme.Due to the large cost of construction,operation and supervision of the tradable credit system,the transaction cost of the credit cards cannot be ignored.In this paper,the author considers the transaction cost ratios in the credit cards market,combines the loss aversion theory,applies the reference dependence model to set up the perceived travel cost function.The variational inequality models under the user equilibrium and market equilibrium conditions in the homogeneous network and the heterogeneous network are formulated respectively.By solving the variational inequality model,the path selection behaviors of travelers under the tradable credit scheme are studied.In the homogeneous network,the different impacts of the implementation of the scheme on the travelers between the various OD pairs and the spatial equity problem are analyzed,while the different impacts on different social parties and social equity issue are studied in the heterogeneous network.In order to improve the equity of the tradable credit scheme,consider the transaction cost ratios as government's adjustment method.By comparing the equilibrium network flow and the equilibrium price of credit cards under different transaction cost ratios,the impact of transaction cost ratios on traveler's path choice,credit card equilibrium price,total system travel cost and equity of tradable credit scheme are analyzed.Furthermore,an utility function is established to concert dual-objective planning into single-objective planning to control total system travel cost as well as improve the equity of the scheme.Optimal transaction cost ratios under different weights can obtained by solving utility function.Comparing with the path flow distribution under congestion pricing,it is found that with the effect of loss aversion,the tradable credit mechanism can guide travelers to select paths which collect less credit cards.In heterogeneous network,the impacts on low-time value travelers and mid-time value travelers are more pronounced.By affecting travelers' path selection,the transaction cost ratios can affect the equilibrium price of credit cards,also indirectly affect the total travel cost of the system and the equity of the tradable credit scheme,thus can be used as a means of government to regulate the tradable credit scheme.As the weight coefficient changes,the degree of emphasis on the equity of the tradable credit scheme changes,and the corresponding optimal transaction cost ratios also differs.