Value of Information in Dispatching Shared Autonomous Mobility-on-demand Systems
Value of Information in Dispatching Shared Autonomous Mobility-on-demand Systems

Author: Jian Wen (S. M.)

Publisher:

Published: 2018

Total Pages: 91

ISBN-13:

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The concept of shared mobility-on-demand (MoD) systems describes an innovative mode of transportation in which rides are tailored as per the immediate requests in a shared manner. Convenience of hailing, ease of transactions, and economic efficiency of crowd-sourcing the rides have made these services very attractive today. It is anticipated that autonomous vehicle (AV) technology may further improve the economics of such services by reducing the operational costs. The design and operation of such an shared autonomous mobility-on-demand (AMoD) system is therefore an important research direction that requires significant investigation. This thesis mainly addresses three issues revolving around the dispatching strategies of shared AMoD systems. First, it responds to the special dispatching need that is critical for effective AMoD operation. This includes a dynamic request-vehicle assignment heuristic and an optimal rebalancing policy. In addition, the dispatching strategies also reflect transit-oriented designs in two ways: (a) the objective function embodies the considerations of service availability and equity through the support of various hailing policies; and (b), the service facilitates first-mile connections to public transportation. Second, this thesis models the interaction between demand and supply through simulation. Using the level of service as interface, this mechanism enables feedback between operators and travelers to more closely represent the choices of both parties. A fixed-point approach is then applied to reach balance iteratively, estimating both the demand volume and the system performance at equilibrium. The results from the simulation support decision-making with regard to comprehensive system design problems such as fleet sizing, vehicle capacities and hailing policies. Third, the thesis evaluates the value of demand information through simulation experiments. To quantify the system performance gain that can be derived from the demand information, this thesis proposes to study two dimensions, level of information and value of information, and builds up the relationship between them. The numerical results help rationalize the efforts operators should spend on data collection, information inference and advanced dispatching algorithms. This thesis also implements an agent-based modeling platform, amod-abm, for simulating large-scale shared AMoD applications. Specifically, it models individual travelers and vehicles with demand-supply interaction and analyzes system performance through various metrics of indicators. This includes wait time, travel time, detour factor and service rate at the traveler's side, as well as vehicle distance traveled, load and profit at the operator's side. A case study area in London is selected to support the presentation of methodology. Results show that encouraging ride-sharing and allowing in-advance requests are powerful tools to enhance service efficiency and equity. Demand information from in-advance requests also enables the operator to plan service ahead of time, which leads to better performance and higher profit. The thesis concludes that the demand-supply interaction can be effective for defining and assessing the roles of AV technology in our future transportation systems. Combining efficient dispatching strategies and demand information management tools is also important for more affordable and efficient services.

Simulation-based Design of Integrated Public Transit and Shared Autonomous Mobility-on-demand Systems
Simulation-based Design of Integrated Public Transit and Shared Autonomous Mobility-on-demand Systems

Author: Yu Xin Leo Chen

Publisher:

Published: 2018

Total Pages: 97

ISBN-13:

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The autonomous vehicle (AV) is poised to be one of the most disruptive technologies in the transportation industry. The advent of three major trends in transportation: automation, on-demand mobility and ride-sharing, are set to revolutionize the way we travel. The forthcoming adoption and commercialization of AVs are expected to have extensive impacts on our road networks, congestion, safety, land use, public transportation (PT) and more. Rapid advances in AV technology are convincing many that AV services will play a significant role in future transportation systems. The advancement of AVs presents both opportunities and threats to transportation. It has the potential to significantly impact traffic congestion, traffic accidents, parking and VMT (vehicle miles traveled), especially for people that are not able to drive such as children and elderly people. Motivated by the potential of autonomous vehicles, authorities around the world are preparing for this revolution in transport and deems this an important research direction that requires significant investigation. This thesis tackled and contributed to three main research questions related to the impact of autonomous vehicles on transportation systems. First, this thesis proposes a simulation-based approach to the design and evaluation of integrated autonomous vehicle and public transportation systems. We highlight the transit-orientation by respecting the social-purpose considerations of transit agencies (such as maintaining service availability and ensuring equity) and identifying the synergistic opportunities between AV and PT. Specifically, we identified that AV has a strong potential to serve first-mile connections to the PT stations and provide efficient and affordable shared mobility in low-density suburban areas that are typically inefficient to serve by conventional fixed-route PT services. The design decisions reflect the interest of multiple stakeholders in the system. Second, the interaction between travelers (demand) and operators (supply) is modeled using a system of equations that is solved as a fixed-point problem through an iterative procedure. In this, we developed demand and supply as two sub-problems. The demand will be predicted using a nested logit model to estimate the volume for different modes based on modal attributes. The supply will use a simulation platform capable of incorporating critical operational decisions on factors including fleet sizes, vehicle capacities, sharing policies, fare schemes and hailing strategies such as in-advance and on-demand requests. Using feedback between demand and supply, we enable interactions between the decisions of the service operator and those of the travelers, in order to model the choices of both parties. Finally, this thesis systematically optimizes service design variables to determine the best outcome in accordance to AV+PT stakeholder goals. Optimization objective functions can be formulated to reflect the different objectives of different stakeholders. In this paper, we specifically propose and develop a simulation-based service design method where we quantify various benefits and costs to reflect the objectives of key AV+PT stakeholders. We simulate the service with different sets of system settings and identify the highest performing set. We employ a case study of regional service contracting to showcase the ability of this method to inform AV+PT service design. We tested our approach with a case study area in a major European city on an agent-based simulation platform, amod-abm. Agent-based simulation has the advantage of capturing individual (agent) behaviors and the interactions of the various individual agents in a realistic synthetic environment where the intent is to re-create a complex phenomenon of mobility on demand service delivered by AV. Although this thesis will focus on a major European city, the general framework and methodologies proposed here can be widely applicable. The thesis concludes that the demand-supply interaction can be effective for designing and assessing the role of AV technology in our mobility systems. Moreover, simulation-based optimization can be an effective method for transit agencies to make decisions that support their overall AV related transport strategy as well as operational planning.

Connected and Autonomous Vehicles in Smart Cities
Connected and Autonomous Vehicles in Smart Cities

Author: Hussein T. Mouftah

Publisher: CRC Press

Published: 2020-12-17

Total Pages: 517

ISBN-13: 1000258971

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This book presents a comprehensive coverage of the five fundamental yet intertwined pillars paving the road towards the future of connected autonomous electric vehicles and smart cities. The connectivity pillar covers all the latest advancements and various technologies on vehicle-to-everything (V2X) communications/networking and vehicular cloud computing, with special emphasis on their role towards vehicle autonomy and smart cities applications. On the other hand, the autonomy track focuses on the different efforts to improve vehicle spatiotemporal perception of its surroundings using multiple sensors and different perception technologies. Since most of CAVs are expected to run on electric power, studies on their electrification technologies, satisfaction of their charging demands, interactions with the grid, and the reliance of these components on their connectivity and autonomy, is the third pillar that this book covers. On the smart services side, the book highlights the game-changing roles CAV will play in future mobility services and intelligent transportation systems. The book also details the ground-breaking directions exploiting CAVs in broad spectrum of smart cities applications. Example of such revolutionary applications are autonomous mobility on-demand services with integration to public transit, smart homes, and buildings. The fifth and final pillar involves the illustration of security mechanisms, innovative business models, market opportunities, and societal/economic impacts resulting from the soon-to-be-deployed CAVs. This book contains an archival collection of top quality, cutting-edge and multidisciplinary research on connected autonomous electric vehicles and smart cities. The book is an authoritative reference for smart city decision makers, automotive manufacturers, utility operators, smart-mobility service providers, telecom operators, communications engineers, power engineers, vehicle charging providers, university professors, researchers, and students who would like to learn more about the advances in CAEVs connectivity, autonomy, electrification, security, and integration into smart cities and intelligent transportation systems.

Shared Mobility on Demand System Design
Shared Mobility on Demand System Design

Author: Mohammad Abdollahi (Industrial engineer)

Publisher:

Published: 2021

Total Pages: 0

ISBN-13:

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Tomorrows mobility will be radically different. Connected, Autonomous, Shared, and Electric Mobility are four main developments that are dramatically altering the automobile industry. We study the shared centralized class of mobility problems which considers a platform of self driving cars. There are new challenges with these systems such as how to balance the idle vehicle, how to price the shared autonomous system, and etc. We are attempting to address the question of how to share passengers ride to maximize satisfaction for riders, and the platform itself. Besides that, to have a good ETA estimate for trips, we develop a data-driven travel time prediction algorithm which can be used in our platform to get a good estimate for scheduling and routing the rides. Finally, we also study the pricing mechanism of these systems using a deep reinforcement learning agent that simulates the rides in New York. We start by studying both static and dynamic (real-time) ride pooling problem with time windows, multiple homogeneous/heterogeneous vehicles, passenger convenience and other business considerations. First, the problems under consideration is modeled as two different static MILP for homogeneous/heterogeneous fleet of vehicles, and also a constraint programming counterpart is provided for the heterogeneous vehicles case. Also to improve the linear relaxation of these models, several pre-processing steps and lifting inequalities are applied. While appealing, exact formulations have integer variables which render them as non-convex optimization problems. Thus, while this approach offers the benefit of system optimality, its formulation here is NP-hard, making it not viable for real world problems. To find a good quality solution, a heuristic decomposition algorithm based on constraint programming and branch and price is proposed to solve static model within a reasonable time for implementation in a real-world situation. Computational results show that the heuristic algorithms are superior compared to the exact algorithms in terms of the calculation time as the problem size (in terms of the number of requests) increases. In phase 2 of this dissertation, we propose a travel time predictive model by developing a integrated multi-step approach to learn the feature space. This multi stage algorithm is initiated by pre-processing task. Subsequently, the feature set is obtained by incorporating some publicly available information. Moreover, a feature engineer ing path is proposed to improve the feature space. This path includes Principal Component Analysis (PCA), geospatial features analysis, and unsupervised learning methods like K-Means and stacked autoencoders. Finally we apply a customized gradient boosting method to estimate travel times and comparing our results with LSTM network which shows superiority of our method in terms of capturing dynamics of traffic through time. Although more data with rare events need to be added in case of experiencing heavy snow or other events which magnifies travel times. Lastly, we developed a fleet management simulation platform where we model pricing problem as a partially observable Markov decision process (POMDP), and DQN agent is developed to estimate fares as a function of real-time interaction with the environment. Fare prices are considered to be continuous and stochastic variables, but for simplicity we have price adjustment in discrete units, and we determine them using a deep neural network (DNN). We compare our algorithm with the one for ride hailing system and see if our pricing mechanism can decrease rejections and cancellation and increase system objective as well as passengers0́9 utility. We illustrate the usefulness of our algorithm by applying it to real-world transportation problem and show that it learns fare estimates to minimize total travel time, maximize revenue, and other weighted objectives. Collectively, this work can be used for designing a ride sharing system of autonomous vehicles in which a controller module with many different predictive and prescriptive analytics engines dispatches vehicles and broadcasts ride fares to optimize system and riders utility.

Demand Estimation and Fleet Management for Autonomous Mobility on Demand Systems
Demand Estimation and Fleet Management for Autonomous Mobility on Demand Systems

Author: Justin Lee Miller

Publisher:

Published: 2017

Total Pages: 166

ISBN-13:

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Mobility On Demand (MOD) systems are creating a paradigm shift in transportation, where mobility is provided not through personally owned vehicles but rather through a fleet of shared vehicles. To maintain a high customer quality of service (QoS), MOD systems need to manage the distribution of vehicles under spatial and temporal fluctuations in customer demand. A challenge for MOD systems is developing and informing a customer demand model. A new proactive demand model is presented which correlates real-time traffic data to predict customer demand on short timescales. Traditional traffic data collection approaches use pervasive fixed sensors which are costly for system-wide coverage. To address this, new frameworks are presented for measuring real-time traffic data using MOD vehicles as mobile sensors. The frameworks are evaluated using hardware and simulation implementations of a real-world MOD system developed for MIT campus. First, a mobile sensing framework is introduced that uses camera and Lidar sensors onboard MOD shuttles to observe system-wide traffic. Through a principled approach for decoupling dependencies between observation data and vehicle motion, the framework provides traffic rate estimates comparable to those of costly fixed sensors. Second, an active sensing framework is introduced which quantifies demand uncertainty with a Bayesian model and routes mobile sensors to reduce parameter uncertainty. The active sensing framework reduces error in demand estimates over both short and long timescales when compared to baseline approaches. Given estimates of customer demand, the challenge for MOD systems is maintaining high customer QoS through fleet management. New automated fleet management planners are introduced for improving customer QoS in ride hailing, ride requesting, and ridesharing MOD operating frameworks. The planners are evaluated using data-driven simulation of the MIT MOD system. For ride hailing, to address the challenge of missed customers, a chance-constrained planner is introduced for positioning vehicles at likely customer hailing locations. The chance-constrained planner provides a significant improvement in the number of served hailing customers over a baseline exploration approach. For ride requesting, to address the challenge of high customer wait times, a predictive positioning planner is introduced to position vehicles at key locations in the MOD system based on customer demand. The predictive positioning planner provides a reduction in service times for requesting customers compared to a baseline waiting approach. For ridesharing, incorrect assumptions on customer preference for transit delays can lead to poor realized customer QoS. A ridesharing planner is introduced for assigning customers to vehicles based on a trained ratings-based QoS model. The ridesharing planner provides robust performance over a range of unknown customer preferences compared to approaches with assumed customer preferences.

The End of Driving
The End of Driving

Author: Bern Grush

Publisher: Elsevier

Published: 2018-06-25

Total Pages: 334

ISBN-13: 0128165103

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While many transportation and city planners, researchers, students, practitioners, and political leaders are familiar with the technical nature and promise of vehicle automation, consensus is not yet often seen on the impact that will result, or the policies and actions that those responsible for transportation systems should take. The End of Driving: Transportation Systems and Public Policy Planning for Autonomous Vehicles explores both the potential of vehicle automation technology and the barriers it faces when considering coherent urban deployment. The book evaluates the case for deliberate development of automated public transportation and mobility-as-a-service as paths towards sustainable mobility, describing critical approaches to the planning and management of vehicle automation technology. It serves as a reference for understanding the full life cycle of the multi-year transportation systems planning processes, including novel regulation, planning, and acquisition tools for regional transportation. Application-oriented, research-based, and solution-oriented rather than predict-and-warn, The End of Driving concludes with a detailed discussion of the systems design needed for accomplishing this shift. From the Foreword by Susan Shaheen: The authors ... extend potential solutions through a set of open-ended exercises after each chapter. Their approach is both strategic and deliberate. They lead the reader from definitions and context setting to the transition toward automation, employing a range of creative strategies and policies. While our quest to understand how to deploy automated vehicles is just beginning, this book provides a thoughtful introduction to inform this evolution. - Offers a workable public transit solution design melding the traditional "acquire-and-operate mode with the absorption of new technology - Provides a step-by-step discussion of digital systems designs and effective regulation-by-data approaches needed for a new urban mobility - Learning aids include case study scenarios, chapter objectives and discussion questions, sidebars and a glossary

Stochastic Modeling and Control of Autonomous Mobility-on-demand Systems
Stochastic Modeling and Control of Autonomous Mobility-on-demand Systems

Author: Ramón Darío Iglesias

Publisher:

Published: 2019

Total Pages:

ISBN-13:

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The last decade saw the rapid development of two major mobility paradigms: Mobility-on-Demand (MoD) systems (e.g. ridesharing, carsharing) and self-driving vehicles. While individually impactful, together they present a major paradigm shift in modern mobility. Autonomous Mobility-on-Demand (AMoD) systems, wherein a fleet of self-driving vehicles serve on-demand travel requests, present a unique opportunity to alleviate many of our transportation woes. Specifically, by combining fully-compliant vehicles with central coordination, AMoD systems can achieve system-level optimal strategies via, e.g., coordinated routing and preemptive dispatch. This thesis presents methods to model, analyze and control AMoD systems. In particular, special emphasis is given to develop stochastic algorithms that can cope with the uncertainty inherent to travel demand. In the first part, we present a steady-state modeling framework built on queueing networks and network flow theory. By casting the system as a multi-class BCMP network, the framework provides analysis tools that allow the characterization of performance metrics for a given routing policy, in terms, e.g., of vehicle availabilities, and first and second order moments of vehicle throughput. Moreover, we present a scalable method for the synthesis of routing policies, with performance guarantees in the limit of large fleet sizes. The framework provides a large set of modeling options, and specifically address cases where the operational concerns of congestion and battery charge level are considered. We validate our theoretical results on a case study of New York City. In the second part, we leverage the insights provided by the steady-state models to present real-time control algorithms. Specifically, we cast the real-time control problem within a stochastic model predictive control framework. The control loop consists of a forecasting generative model and a stochastic optimization subproblem. At each time step, the generative model first forecasts a finite number of travel demand for a finite horizon and then we solve the stochastic subproblem via Sample Average Approximation. We show via simulation that this approach is more robust to uncertain demand and vastly outperforms state-of-the-art fleet-level control algorithms. Finally, we validate the presented frameworks by deploying a fleet control application in a carsharing system in Japan. The application uses the aforementioned algorithms to provide, in real-time, tasks to the carsharing employees regarding actions to be taken to better meet customer demand. Results show significant improvement over human based decision making.

The Multi-Agent Transport Simulation MATSim
The Multi-Agent Transport Simulation MATSim

Author: Andreas Horni

Publisher: Ubiquity Press

Published: 2016-08-10

Total Pages: 620

ISBN-13: 190918876X

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The MATSim (Multi-Agent Transport Simulation) software project was started around 2006 with the goal of generating traffic and congestion patterns by following individual synthetic travelers through their daily or weekly activity programme. It has since then evolved from a collection of stand-alone C++ programs to an integrated Java-based framework which is publicly hosted, open-source available, automatically regression tested. It is currently used by about 40 groups throughout the world. This book takes stock of the current status. The first part of the book gives an introduction to the most important concepts, with the intention of enabling a potential user to set up and run basic simulations. The second part of the book describes how the basic functionality can be extended, for example by adding schedule-based public transit, electric or autonomous cars, paratransit, or within-day replanning. For each extension, the text provides pointers to the additional documentation and to the code base. It is also discussed how people with appropriate Java programming skills can write their own extensions, and plug them into the MATSim core. The project has started from the basic idea that traffic is a consequence of human behavior, and thus humans and their behavior should be the starting point of all modelling, and with the intuition that when simulations with 100 million particles are possible in computational physics, then behavior-oriented simulations with 10 million travelers should be possible in travel behavior research. The initial implementations thus combined concepts from computational physics and complex adaptive systems with concepts from travel behavior research. The third part of the book looks at theoretical concepts that are able to describe important aspects of the simulation system; for example, under certain conditions the code becomes a Monte Carlo engine sampling from a discrete choice model. Another important aspect is the interpretation of the MATSim score as utility in the microeconomic sense, opening up a connection to benefit cost analysis. Finally, the book collects use cases as they have been undertaken with MATSim. All current users of MATSim were invited to submit their work, and many followed with sometimes crisp and short and sometimes longer contributions, always with pointers to additional references. We hope that the book will become an invitation to explore, to build and to extend agent-based modeling of travel behavior from the stable and well tested core of MATSim documented here.