A tabu search–based algorithm is developed in this study and applied for optimizing a variable speed limit (VSL) control system. A macroscopic traffic flow model is used to predict the traffic states over the prediction horizon. The objective of the VSL control is to minimize the total value of travel time and total value of speed variation on the selected freeway segments. Sensitivity analyses are conducted for the tabu search parameters. Different weight sets of the objective function are selected and tested. Solution qualities from the tabu search algorithm and sequential quadratic programming (SQP) algorithm are compared. Numerical results clearly indicate that the proposed tabu search outperforms the SQP, which is used as a benchmark. The control results also show that the VSL can effectively reduce total travel time and total speed variation at a lane drop bottleneck. The relationships between the number of VSL control segments and total travel time, total speed variation, and combined objective function value corresponding to different weight sets are also given.
Dr. Wei (David) Fan currently serves as a tenured full professor in the Department of Civil and Environmental Engineering (CEE) at The University of North Carolina at Charlotte (UNCC). He is the Director of the USDOT University Transportation Center for Advanced Multimodal Mobility Solutions and Education (CAMMSE – http://cammse.uncc.edu/), a five-year $7.7 million multi-campus research center funded by USDOT. Dr. Fan holds a Ph.D. (May 2004) in Civil Engineering – Transportation from the University of Texas at Austin (Hook ’em Horns!). He was a Senior Analytical Optimization Software Developer for the R&D Department at SAS Institute Inc. located in Cary, North Carolina from June 2004 – August 2006.
Dr. Fan’s primary research interests include big data analytics for transportation (travel demand analysis, and discrete choice modeling); connected and autonomous vehicles (technologies, and impacts); multimodal transportation and shared mobility (non-motorized transportation including bicycle and public transit systems planning and operations, carsharing, and bike-sharing); traffic system operation and control (traffic simulation, and active traffic management including variable speed limits and managed lanes); and transportation system analysis and network modeling (equilibrium-based traffic assignment, network design and highway improvements, travel time reliability, freeway bottleneck identification and mitigation, and congestion pricing). Dr. Fan serves as an associate editor of IEEE Transactions – Intelligent Transportation Systems, an associate editor of ASCE Journal of Transportation Engineering, Part A: Systems, and an associate editor of International Journal of Transportation Science and Technology while also serving as a member of three other transportation journal editorial boards. Dr. Fan also serves as a member on the National Science Foundation (NSF) review panels, the National Cooperative Highway Research Program (NCHRP) panels, the Transit Cooperative Research Program (TCRP) panel and three Transportation Research Board (TRB) committees. He has been working as an active ad hoc reviewer for more than 20 prestigious journals as well as the national Highway Capacity Manual (HCM) (2010 version). He was selected by the students as the Best Civil Engineering Professor of the Year 2007 and was a proud ASCE Excellence in Civil Engineering Education (ExCEEd) Teaching Fellow in 2007.
Dr. Fan has been and is involved in many sponsored projects (over 14 million dollars in funding), having been principal or co-principal investigator on many research studies for the U. S. Department of Transportation (USDOT), Federal Highway Administration (FHWA), National Cooperative Highway Research Program (NCHRP), SHRP2 Education Connection, Texas Department of Transportation (TxDOT) and North Carolina Department of Transportation (NCDOT). He had published more than 100 journal articles, proceeding papers and technical reports on big data analytics for transportation, connected and autonomous vehicles, multimodal transportation and shared mobility; traffic system operation and control, and transportation system analysis and network modeling . He is a registered professional engineer in Texas.