A parallel computing approach to solve traffic assignment using path-based gradient projection algorithm.

• A tailored Parallel Block-Coordinate Descent algorithm for user equilibrium problem. • A novel rule to group indices (OD pairs) into blocks. • Parallelize the computationally expensive components in the iGP algorithm. • Test computation efficiency of the proposed algorithm on large transport networks. This paper presents a Parallel Block-Coordinate Descent (PBCD) algorithm for solving the user equilibrium traffic assignment problem. Most of the existing algorithms for the user equilibrium-based traffic assignment problem are developed and implemented sequentially. This paper aims to study and investigate the parallel computing approach to utilize the widely available parallel computing resources. The PBCD algorithm is developed based on the state-of-the-art path-based algorithm, i.e., the improved path-based gradient projection algorithm (iGP). The computationally expensive components in the iGP are identified and parallelized. A parallel block-coordinate method is proposed to replace the widely used Gauss-Seidel method for the procedure of path flow adjustment. A new rule is proposed to group OD pairs into different blocks. The numerical examples show that the implemented PBCD algorithm can significantly reduce the computing time. [ABSTRACT FROM AUTHOR]