Monthly archives: January, 2015

The Promises and Pitfalls of OD Table Estimation from Ground Counts

Estimating origin-destination (OD) tables from ground counts can be controversial.  In many cases the number of variables of the estimation problem greatly exceeds the number of data points.  This means that additional information must be gotten from somewhere, and the quality of that information is often suspect. QRS II contains many different methods for performing …

Convergence Criteria for Equilibrium Traffic Assignments

If you are reading this article you probably know something about equilibrium traffic assignment and how it is done in at least one travel forecasting package.  Traditional methods of equilibrium traffic assignment, say Frank-Wolfe decomposition and MSA (method of successive averages) found in wide use around the world, converge to an equilibrium solution rather slowly. …