Impact Of Ridesharing On The Variance Of Car Increments

With the fast development of real-time matching platforms such as Didi Shunfengche and Dida Pingche,ridesharing becomes popular around the world in recent years.While most people believe that ridesharing reduces the necessity of car ownership therefore has an effect on decelerating the increase of vehicles in a city,this paper points out that its impact on car ownership is double-edged.On one hand,ridesharing provides an attractive travel mode,therefore may persuade some travelers to give up their vehicle purchase plan;on the other hand,the cost of private car driving is shared,so that some travelers who originally cannot afford the cost of car usage may be induced to purchase cars.In this paper,we model the car-purchasing and travel mode choices of travelers whose value of time is heterogeneously distributed and increases over time.Before the existence of ridesharing,travelers can choose to take public transit or drive alone.After the appearance of ridesharing,those car owners can choose to be a driver of ridesharing,a rider of ridesharing or a solo driver,while those non-car travelers can choose to take public transit or choose to be a rider of ridesharing,or choose to purchase cars to be a driver of ridesharing or to be a solo driver.Under the assumption that the driver bypass time and passenger waiting time are both constant and all travelers choose the least-cost mode,this paper analyzes the variance of travelers' mode choices and car ownership from the base year to the target year due to the increase of travelers' value of time.The calculation model is given to demonstrate the impact of ridesharing on the variance of car increments.Based on the model,numerical examples are conducted.As shown in the numerical example,ridesharing may accelerate or decelerate the increase of car ownership,depending on the design of driver-rider cost sharing strategies,private car travel time,fuel price,and public transportation cost.Then,we further relax the assumption that the driver detouring time and passenger waiting time are constant,and establish an equilibrium model that takes into account the interaction between the driver/rider detouring/waiting time and travelers' mode choices.Then,Brouwer's fixed point theorem is used to test the existence of equilibrium and the equilibrium conditions under Brouwer's theorem are given.