A gradient approximation approach for adjusting temporal origin-destination matrices

"The temporal demand matrix is an essential input to both on-line and off-line applications. of dynamic traffic assignment (DTA). This paper presents a new method to solve the simultaneous. adjustment of a dynamic traffic demand matrix, searching for a reliable solution. with acceptable computational times for off-line applications and using as an input traffic. counts and speeds, prior O–D matrices and other aggregate demand data (traffic demand. productions by zone). The proposed solving procedure is a modification of the basic Simultaneous. Perturbation Stochastic Approximation (SPSA) path search optimization method;. it can find a good solution when the starting point (the seed matrix) is assumed to be. ‘‘near” the optimal one, working with a gradient approximation based on a simultaneous. perturbation of each demand variable."