Planners have long relied on traffic operations analysis software to “calculate” future conditions: Input current conditions, identify what the proposed project would change about them, add some growth factors, assume some travel routes and the number of passengers in each car, and voila! Your software predicts the future. Mitigate some impacts with changes to traffic signal timing or physical changes and you’ve made them disappear. Maybe that’s viable for a short-term future. But two decades in advance?

In the November 2015 issue of APA Planning magazine, David Fields offers an insightful look at the true value of models.