It May Take Longer Before It Gets Faster

As an Indiana traffic engineer, we study traffic problems all throughout…wait for it… Indiana. And we have come to understand that each community has a different definition of what they consider a traffic “problem.” Fortunately, computer models are available to standardize traffic problems by converting intersection geometry and peak hour traffic volumes to a “level of service” rating (LOS).

The LOS represents vehicle delay — typically calculated during peak hour traffic conditions. The rating can be determined for each individual lane of traffic (including turn lanes) or, for the overall intersection. Ratings range from “A” to “F” where a level of service “D” is considered passing (just like school). And keep in mind, a level of service “F” does not always mean something must be done. For example, almost every driveway along almost every highway experiences a LOS of  “F” (especially if you are trying to exit left onto the roadway during the peak hour).

The LOS of most intersections can be improved by adding turn lanes (or making turn lanes longer), adding a traffic signal (or adding turn arrows), or converting a traditional intersection to a roundabout. In some cases, the only way to improve the LOS is by adding through lanes. This level of improvement is identified in the community’s thoroughfare plan. Additional options may include new roadway corridors, perimeter roads, or modifying traffic patterns (e.g., 1-way vs 2-way, restricting certain turn movements, prohibiting trucks, etc.).

In general, traffic increases every year. It’s the cumulative result of increased development both near and far. It’s like what Benjamin Franklin said (or was it my uncle?), “Where you have a lot of cars, you have a lot of traffic.”

Remember, transportation planning is not a static task. Traffic growth and traffic patterns change and should be monitored to ensure transportation plans are not only doable but also, make sense. And although the best time to plan for traffic growth may have been ten years ago — the second best time is today.

Chet Skwarcan (traffic engineer, author, unique insights) with over 25 years of traffic engineering experience — online help available at