Modeling And Analysis Of City Commuting Behavior Based On Tradable Credit Scheme

With the progress of urbanization,the permanent population of many big cities have experience an increasing growth and so does the enormous amount of private cars.Accordingly,the commuting congestion is becoming more serious,heavily influencing the quality of citizens and restricting the sustainable development of the city as well.Singapore,London and some others cities apply the instrument of congestion pricing to management the traffic demand,which turn out to be an efficient policy to alleviate the jam.In China,whereas,it could not be implemented in a short time due to all kinds of reasons.Then at this background,a novel concept of tradable credit scheme is proposed by scholars.It's none of business of toll and more equitable.Therefore,such a policy is supposed to be accepted by citizens.In reality,with the concept of "Internet Plus" and sharing economy infiltrating in our daily life,carpooling has become a popular travel mode.Besides,many cities have stepped into the so called "Subway Era".The developed subway net makes the mode of park and ride more efficient.Therefore,a feasible method to manage the traffic demand efficiently is encouraging modal shifts from a low occupancy mode to a higher one.Accordingly,the paper constructs a series models as follows.In the beginning,from the commuters' acceptable perspective,using the utility function of constant elasticity of substitution(CES),the paper formulates a fixed demand commuting model based on the combination policy of tradable credit scheme and encouraged carpooling,in which a coefficient for government support on carpooling behaviors is added into the constraint condition of travel budget,and then makes an analysis on commuters' mode choices.The results show that this combination policy can effectively guide the solo commuters become the carpool commuters,and the commuting individuals can reduce their travel budget without damaging their original commuting demand,although the budget reduction for individuals preferring solo commuting is relatively small.Additionally,it shows that there exists a feasible region for setting the adjustment factors and encouraged carpooling coefficients,and there is a corresponding lower bound of adjustment factor for different encouraged carpooling coefficient.Then based on a linear mono centric city,with the explicit consideration of user heterogeneity,i.e.,each commuter has a different value of time(VOT),this paper constructs optimal Park and Ride(P&R)location along the subway and mode choice equilibrium models.On the base of the models,we further examine the impact of the tradable credit scheme(TCS)on the mode choice equilibrium.Study shows that TCS could effectively attract commuters divert from auto-mode to P&R and the generalized cost of most commuters decrease.Although the total cost of the system rises a little,the congestion in the CBD can be alleviated significantly.Finally,for a given traffic system consists of an urban arterial road and a parallel railway equipped with continuous park-and-ride stations.Commuters follow continuous uniform distribution along the highway.There are three mode choices available in the traffic system,namely,driving all the way,taking railway entirely and park-and-ride in an appropriate station.To analysis the impact of tradable credit scheme on commuting mode choice,a hierarchical Logit stochastic model is constructed based on the utility theory.The model is solved numerically through transforming it into a discrete version using the successive iteration approach.The results show that,at equilibrium,tradable credit scheme could attract commuters living in the outskirt to divert from driving all the way to park-and-ride mode but has little effect on commuters near the center of the city.