Integrated Optimization Of Fare Strategy And Fare Levels For Subway And Bus In A Transit Corridor

The integration of fare strategy and fare levels for public transits is one of the important portions of urban public transit system,which can impact the public transportation of citizens.The fare strategy expresses the pricing policy of public transit and the fare levels are the specific toll rates in the fare strategy.Based on the main research background of a transit corridor in the inner city served by subway and bus services,the fare strategy and fare levels of two transit services are optimized jointly,and then transfer pricing discount policy is integrated with the fare strategy in order to obtain the most suitable fare structure.For this purpose,a bi-level program is formulated,of which the upper level aims to maximize the social welfare and the lower level is a variable-demand stochastic user equilibrium assignment model.The genetic algorithm is applied to solve the bi-level program while the method of successive averages is adopted to solve the lower-level model.Finally,a series of numerical experiments is carried out to verify the details of the study.The major relevant contents are as follows:Considering the advantage of differential fare strategy,the paper proposes new fare strategies,which are area-based and combination fare strategy.These fare strategies are used to control passengers’ behavior,and then attract more passengers to choose public transit.Then,taking the flat fare strategy as an example,the factors considered in the fare planning are confirmed.The main analysis contents include:First,there are some delay risks in travel time for a certain distance by transit mode in the inner city.The risks may be caused by the uncertainty from operating environment of transit mode or random factor in the inner city.Especially for the commuting during morning peak hour,considering the delay risk taken by transit mode,passenger forecasts the necessary travel time in the trip according to experience,and then chooses the suitable travel path.In optimization of transit fares,it is essential to take into account the passenger subjective evaluation of the delay risk due to her or his mode choice as well as the objective conditions affecting the choice of travel routes.The results show that the effect of the passenger subjective evaluation of the delay risk on travel behavior is significant and that the optimal fares are reduced compared with the results that are achieved without regard for the passenger subjective evaluation.Second,considering the stop spacing difference between subway and bus service,passengers served by both services are classified into three types according to their trip paths.One of these types is the traditional travel group as well as the background of previous literature that don’t involve the difference in stop distance between two services.Other types are the specific travel groups under the background of this paper.The fares of the two services are optimized in an integrated model that captures the interaction of different passenger type trip and the influence of it on optimal fares.The results show that 1)it is of great significance to embed the factor of stop spacing difference between subway and bus services into the integrated optimization of fares of the two services,otherw:ise overcrowding may emerge in a set of routes in each service line,2)the optimal fares of each service can increase and the difference between fares of two services is reduced considering the stop spacing difference.With the determined factors involved in fare planning,the optimal results of flat fare strategy are saved as a reference.Then,these new fare strategies are compared with distance-based fare strategy which is an existing differential strategy in order to acquire the most suitable fare strategy.The results show that 1)all three differential fare strategies play a better role in promoting social welfare and travel demand compared with flat fare strategy,2)the combination fare strategy is the most suitable fare strategy which has the highest social welfare and result passenger demand.Further more,the transfer pricing discount and fare strategy are optimized jointly,and then examines how the fare strategies proposed require transfer pricing discount policy and verifies the most suitable fare structure.The results show that 1)the requirement of the transfer pricing discount policy is different for proposed fare strategies,i.e.the strongest for the flat fare strategy and the weakest for area-based fare strategy,2)the integration of the combination fare strategy and transfer pricing discount policy which generates the greatest value of objective function is the most fare structure for the situation in research.In addition,extending study is conducted based on the background of an public transit corridor between urban district of Dalian and Lushun.The results of model calculation are compared with the survey data aiming to analyze and illustrate the difference of main factors influencing passenger behavior between public transit corridor in urban and public transit corridor between urban districts.Referring to the related information of existing public transit,the implementation of fare strategy with the probable transfer discount policy is analyzed and compared with the existing fare strategy,and the distribution of passengers in different transit lines are predicted and analyzed under the fare strategy in the future public transit channel by applying the verified model.