Increasing Vehicle Occupancy through Shared-Ride Mobility Services 

Abstract
The overarching goal of this research is to increase vehicle occupancy in metropolitan regions through mobility services wherein travelers share rides with others. This talk will discuss three different research avenues to meet this goal. The studies provide insights to transportation planners, policymakers, and mobility service providers regarding future transportation systems with shared mobility services (particular those enabled by automated vehicles) playing a large role.
The first research direction involves collecting data through stated-preference surveys to model travelers’ willingness to use a flexible transit mode (in the Chicago region). The key findings of this research, published in TR Part C, indicate that: (i) there is a decrease in disutility associated with waiting at home for a flexible transit vehicle rather than waiting outside for a fixed-route transit vehicle; (ii) there is strong commute mode inertia among all travelers but particularly car commuters that will make it challenging to cause large modal shifts away from the private vehicle to transit modes; (iii) travelers favor flexible transit when there is precipitation or cold weather.
The second research direction involves determining the operational benefits of shared-ride services relative to mobility services without shared rides from the perspective of a mobility service provider. To uncover the operational benefits of shared-ride mobility services (as well as operational challenges), this study involved developing and applying a dynamic stochastic agent-based simulation model. Findings indicate that even if travelers are only willing to detour 5-10% off their shortest path in a shared-ride vehicle to pick up another traveler, allowing shared rides significantly increases the service rate of a fixed vehicle fleet compared to a mobility service without shared rides. This benefit arises as a direct result of the economies of density and network effects present in shared-ride services. This research was recently published in TR Part A.
The third research direction involves developing path-finding strategies for the vehicles in a shared-ride mobility service. The key idea behind this research is that as shared-ride vehicles travel from one pickup/drop-off location to the next drop-off/pickup location, the vehicle should not simply choose the shortest travel time path; rather, the vehicle should consider both the path's travel time and the path's proximity to other demands. By considering proximity to demand, it is likely that the shared-ride vehicles can increase the number of shared rides the service provides. This is an ongoing research project funded by Caltrans and we expect to have results before mid-July.