![\"\"](\"http:\/\/depts.washington.edu\/pactrans\/wp-content\/uploads\/2019\/07\/Optimal-e1563218444914.jpg\")
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After more than two years of dedicated work, WSU Civil and Environmental Engineering Assistant Professor, Ali Hajbabaie<\/a>, and Graduate Research Assistant, Rasool Mohebifard<\/a>, got their paper accepted, published, and downloaded more times than most in Transportation Research Part B: Methodological<\/a><\/em> last winter.\u00a0<\/span><\/p>\n Their piece, titled, \u201cOptimal network-level traffic signal control: A benders decomposition-base solution algorithm,\u201d focuses on the network-level traffic signal timing optimization problem and explores the ways in which it can be solved.<\/span><\/p>\n The problem is expressed as a Mixed-Integer Nonlinear Program (MINLP), which is based on the Cell Transmission Model (CTM). This allows it to consider closed-form constraints and capture the fundamental flow-density diagram, ultimately getting rid of the flow holding-back problem.<\/span><\/p>\n The MINLP is then divided into an Integer Program (IP), or the \u201cmaster problem\u201d, and new MINLP, otherwise known as the \u201cprimal problem\u201d, using a solution algorithm based off of the Benders decomposition technique.\u00a0<\/span><\/p>\n The image above compares the runtimes of solving the primal problem versus the master problem.\u00a0<\/span><\/p>\n Some of the research highlights include:\u00a0<\/span><\/p>\n\n