Optimization of Mode Share for Low-Carbon-Oriented Urban Passenger Transportation System

To develop the public transportation system and change the passenger transport mode share, as well as to control the resorting to private cars have been considered one of the most effective methods to reduce carbon emission. This paper aims at determining an optimal mode share scheme for the urban passenger transportation system, which meets the carbon emission limitation and the government investment constraint at the lowest social cost. This optimal mode share scheme could work as a suggested mode split target for a low-carbon city. Stackelberg game theory based bi-level modeling is used as the modeling approach because there are multiple decision makers involved. The objective of the upper level model will work as decision making assistance for the government in determining an optimal mode share scheme of the urban passenger transportation system, which meets the low carbon emission, the government investment and some other constraints, at the lowest social cost, including pollution treatment fee for CO₂ and construction fee for different traffic systems in different district. Classic UE equilibrium based automobile traffic flow assignment model and Non-UE transit flow assignment method on the network is the second level; it is built on behalf of users' consideration, and to reflect the performance of network with the changing of mode share, as well as to build the loop between two levels with the changing of average speed of vehicles. Algorithm for bi-level modeling is also studied and a sample network is used to test the workability of the proposed modeling approach.