Travel Demand Model
The travel demand model is a computer-based tool used to determine the future volumes and capacities of roadways throughout the region.
The TDM uses data from Comprehensive Plans to identify areas where future residential, commercial and industrial growth will occur. The TDM then makes assumptions as to how much more traffic will be generated on various roadways based on this growth. This allows us to know the Level of Service (LOS) of roadways (the number of vehicles on a road compared to how many vehicles it was designed to carry). We measure LOS on an scale from A to F.
In the Flint Hills Region, we tend to design to an LOS of "C", which would mean that traffic is moving at an acceptable speed (shown on the maps as "green"). Anything below an LOS of "C" is considered "congested" by our region's definition. Knowing which roadways are likely to be congested in the year 2040, we are able to proactively design and build projects that will relieve future capacity issues. This then allows our limited financial resources to be utilized for projects that have long-term benefits.
It should be noted, that the model is only one tool used to determine a roadways capacity or a project's long-term viability. There are roadways shown with a lower LOS that will not be expanded to increase capacity (downtown streets, civic streets, roadways with higher pedestrian traffic), because they aren't intended to move traffic through quickly. The model also is not able to understand the impact of intersections on travel times or congestion. For instance, several of the regions roadways that the model shows as "At" or "Over Capacity" may be able to handle the number of vehicles on the links (the roadway), but see delays because of the nodes (intersections). In these situations, adding additional lanes or increasing capacity will not solve the issue.