Title
Large-Scale Traffic Signal Offset Optimization
Abstract
The offset optimization problem seeks to coordinate and synchronize the timing of traffic signals throughout a network in order to enhance traffic flow and reduce stops and delays. Recently, offset optimization was formulated into a continuous optimization problem without integer variables by modeling traffic flow as sinusoidal. In this article, we present a novel algorithm to solve this new formulation to near-global optimality on a large scale. Specifically, we solve a convex relaxation of the nonconvex problem using a tree decomposition reduction, and use randomized rounding to recover a near-global solution. We prove that the algorithm always delivers solutions of expected value at least 0.785 times the globally optimal value. Moreover, assuming that the topology of the traffic network is “tree-like,” we prove that the algorithm has near-linear time complexity with respect to the number of intersections. These theoretical guarantees are experimentally validated on the Berkeley, Manhattan, and Los Angeles traffic networks. In our numerical results, the empirical time complexity of the algorithm is linear, and the solutions have objectives within 0.99 times the globally optimal value.
Year
DOI
Venue
2020
10.1109/TCNS.2020.2966588
IEEE Transactions on Control of Network Systems
Keywords
DocType
Volume
Convex relaxation,offset optimization,semidefinite programming,traffic control,traffic signal timing,tree decomposition
Journal
7
Issue
ISSN
Citations 
3
2325-5870
0
PageRank 
References 
Authors
0.34
0
4
Name
Order
Citations
PageRank
Yi Ouyang14310.16
Richard Y. Zhang2106.92
Javad Lavaei358771.90
Pravin Varaiya42543298.93