Evaluation of Vehicle Assignment Algorithms for Autonomous Mobility on Demand

The term “Mobility” is gaining new perspectives. Due to the paradigm shift driven by information technologies and autonomous vehicles, on-demand mobility services have experienced significant growth. Operating such a service efficiently is a challenging task. Especially, assigning vehicles to customers plays a vital role in this regard. To meet a satisfactory level of service while keeping the operational costs to a minimum requires efficient assignment strategies. Work summarized in this paper utilizes several shared and nonshared assignment algorithms in order to propose a methodology to assess the effects on the overall system performance for an Autonomous Mobility on Demand system. Selected algorithms are tested in a theoretical network with real-world taxi data with the help of microscopic traffic simulation software Simulation of Urban Mobility. Simulation scenarios are generated for both varying demand levels and increasing fleet sizes. Results suggest that for high demand levels and small fleet sizes, shared algorithms outperform nonshared algorithms for every performance measure chosen: total vehicle kilometers traveled, the ratio of empty fleet kilometers, average passenger waiting time for pick up, and the number of customers served in a period

Analysis on Effects of Driving Behavior on Freeway Traffic Flow: A Comparative Evaluation of Two Driver Profiles Using Two Car Following Models

Car-following (CF) behavior is the most abstract form of driving action and, CF behavior modeling has been one of the core aspects of traffic engineering studies for several decades. The literature about CF behavior modeling is vibrant and still evolving. Furthermore, the effect of CF models on the traffic flow performance through case studies on different traffic facilities is still being investigated. To shed light on this matter, this study presents a microsimulation-based case study considering a freeway stretch in Istanbul, Turkey, employing two different CF models, i.e., Intelligent Driver Model (IDM) and Wiedemann 99 through scenarios. Simulation of Urban Mobility (SUMO) is utilized as the microsimulation environment. Both CF models are calibrated according to the measurements. Scenarios for the comparative evaluation are setup based on the questions "What if German drivers used this freeway stretch? How much would the traffic flow performance change?" Using different case studies conducted in German Freeways on the literature, simulation model parameters are obtained for both models and, simulation analyses are performed. Traffic flow performances are evaluated based on the selected performance measures, such as throughput and total travel time. According to the findings, it is seen that results differ significantly between scenarios. We elaborate on the differences obtained and discuss the implications on different scenarios which are handled through different CF models