Understanding traffic flow at and near capacity

A new approach to understanding the observed behavior of freeway traffic has been proposed based on catastrophe theory. Catastrophe theory is a mathematical approach that allows for both continuous and discontinuous variables. This article summarizes those ideas and illustrates them with data from one freeway system in southern Ontario. The important part of this new approach is that it not only resolves the observed speed discontinuity but also offers a new procedure for managing freeway operations. This article presents a description and illustration of how the approach works. Mathematical and statistical approaches are available.