Im Rahmen der Ringvorlesung "Kooperatives Verkehrsmanagement" referiert Prof. Barrett Thomas.
Barrett Thomas vom Department of Management Sciences at the Tippie College of Business of the University of Iowa in Iowa City, Iowa wird zum Thema „Optimizing for Costs and Emissions in Vehicle Routing in Urban Areas“ referieren. Der Vortrag findet am Donnerstag, 17.11.2016 ab 16 Uhr im Raum Volkswagen 1 (NFF-Forschungsneubau) statt.
The minimization of emissions has become an important topic in vehicle routing research. Still, minimizing costs remains one of the most important objectives for logistics service providers, and it is not clear how minimizing emissions impacts total costs. In urban areas, speeds can vary significantly due to congestion over the course of the day, and the total cost and fuel consumption associated with different paths between customers can vary based on travel speed and the load on the vehicle. To compute cost-effective and environmental-friendly routes in urban areas appropriately, large amounts of detailed speed data are needed in adapted vehicle routing algorithms. This paper compares the total cost (based on combined driver and fuel costs), fuel consumption (emissions), distance, and travel time for routes resulting from optimizing each of those measures. We explore the impact of multiple considerations on these measures as well as the structure of the routes themselves. We consider driver hourly cost, fuel cost, customer geography (inner city, suburban, mixed), customer load distribution (homogeneous versus heterogeneous), vehicle size (standard versus heavy), fleet composition (homogeneous versus heterogeneous), traffic congestion (rush hour versus non-rush hour), and whether or not the vehicle is delivering or picking up loads at customers. This extensive set of experiments is conducted based on the LANTIME algorithm, which is a tabu search heuristic that we have adapted to consider complex cost functions and load information. We use a large speed database with millions of speed observations from the area of Stuttgart, Germany, as input for our computational analysis. The results show that the total cost objective produces significantly different routes for mixed fleets, heterogeneous customer demands, and suburban and mixed geography locations. We also observe features about how the structures of the routes differ when total costs are minimized as compared with fuel, such as how heavy vehicles are utilized in mixed fleet compositions and when customers with larger loads are visited.
Barrett Thomas is an Associate Professor and a Gary C. Fethke Faculty Research Fellow in the Department of Management Sciences at the Tippie College of Business of the University of Iowa in Iowa City, Iowa. Professor Thomas’ research focuses stochastic sequential decision making with applications primarily in stochastic and dynamic vehicle routing and in workforce planning. His work has appeared in journals such as Operations Research, Transportation Science, INFORMS Journal on Computing, and the European Journal of Operational Research. His research has been sponsored by the United States National Science Foundation as well as private industry. Professor Thomas also serves as an associate editor for Transportation Science, IIE Transactions, and Surveys in Operations Research and Management Science. Professor Thomas currently serves as the Past President of the INFORMS Transportation Science and Logistics Society having served as the Society’s President in 2015. In 2011 and 2012, Professor Thomas served as an INFORMS Board member in the role of Vice President Sections/Societies. In this capacity, he chaired the INFORMS Sections/Societies Committee and Subdivisions Council. INFORMS is the world’s largest professional society devoted to analytics and operations research professionals. Professor Thomas is also a Trustee of Grinnell College and has served as the Vice Chair of the Board in 2014 and 2015 and is now the Chair of the Board’s Trustee & Trustee Organization Committee.