【正文】 l G (2020). Forecasting environmental equity: air quality responses to road user charging in Leeds, UK. Journal of Environmental Management, , , . 453。 2020 IEEEDOI 449 Traffic congestion, resulting in the increase of travel time, traffic accident, energy consumption and environment deterioration, has produced numerous economic losses. It was reported that economic loss caused by traffic congestion amounted to 40 million Yuan per year in Beijing and 1/3 of GDP in Shanghai in 2020 [2]. In many cites, traffic congestion has seen as a hindrance to economic development. Any sustainable transportation management polices should meet the goals of improving the effects of transport on economic development, and without adversely impacting the environment and the potential for further economic growth. How effective would congestion pricing strategy be in reducing congestion, lowering pollutants and greenhouse gas emissions, cutting fuel use, and reducing other adverse impacts of current transportation system? The basic economic principles of congestion pricing can be illustrated in Figure 1. Theoretically, individual users decide whether or not to use a particular road by weighing the costs they will to bear against the benefits to themselves. Total social benefits can be measure by the area under D in Figure 1. The user costs indicated on the MPC curve reflect only the costs borne by each user as new users (. “marginal” users) are added. However, the marginal user occasions additional social costs, such as air pollution and delay to other users, which he does not bear. The total costs borne by each marginal user and the social costs occasioned by him are the marginal social costs of each trip. Marginal social costs are indicated by the MSC curve in figure 1. Figure 1 Effect of congestion pricing If there are n vehicles in the transport system, and mean user cost is represented by MPC, one marginal user added will increase mean user cost to MPC+△MPC. Thus the marginal social costs can be formulated as [3]: MPCnMPCMPCnMPCMPCMPCnMSCΔ+Δ+=?Δ++= ))(1( The unregulated ‘notoll’ equilibrium occurs at the intersection of MPC and D, resulting in an equilibrium flow of q2 and an equilibrium price of C2. However, the social optimal is found in Figure 1 at the intersection of MSC and D, where the marginal willingness to pay for trip is C3, and the flow is q1, which is less than in the unregulated equilibrium. Congestion pricing makes the system optimal by charging marginal congestion cost imposed by a traveler on others [4]. Congestion pricing is an important means of transportation demand management, and initially only affects transportation decisions. Practices prove that congestion pricing can effectively regulate traffic travel time and space distribution, promote effective utilization of road resources, and enhance the efficiency of transportation operations. Congestion pricing implementation in Singapore has showed that traffic volumes decreased by 17% in peak time periods [5], and London’s experience also indicated that pricing schemes was successful [6]. As we convert all the savings in travel time resulting from decreased congestion to moary units, we can conclude that the reduction of congestion will promote sustainable economic development. Toll will affect travelers’ budget constraints and will result not only in mode switching but also in broader changes in the economy that will be acpanied by the geographic redistribution of trips. Some concerns that congestion pricing may have negative effects on the economy of the central area, particularly on retail [7]. A counterargument, however, states that the reduced congestion is supposed to lower the costs of the downtown businesses, making them more petitive. The location of retail activity, on the other hand, is also driven by individuals’ preferred shopping locations. As well known, individuals tend to shop near their place of residence, so retail firms cannot easily move out of the core area, because so many people live in center area. This dependence on customer convenience explains why retail production decreases less