Application of Traffic Assignments by a Paired Alternative Segments Algorithm

Bar-Gera proposed a new algorithm for the traffic assignment problem that promises to produce highly precise solutions by identifying a list of paired alternative segments (PAS) on origin-based sub-networks and shifting flow with PAS. This paper systematically studies the theory of traffic assignment by PAS algorithm proposed by Bar-Gera, especially introducing key steps of the algorithm, such as establishing PAS structure, shifting flow, and equalizing proportions between origins. Then the paper tests the PAS algorithm with different sizes of road networks to demonstrate the efficiency and convergence precision of the algorithm. In addition, this paper also compares the PAS algorithm with the gradient projection (GP) algorithm to analyze these two algorithms’ efficiency and convergence precision. The comparison result indicates that when the required accuracy is not high, their efficiency is the same, but when the required accuracy is high, the PAS algorithm is better.