Probe vehicle data provide a ""flexible and robust"" basis for identifying inefficient arterial corridors.
The Iowa DOT study used already-purchased traffic data in lieu of expensive field infrastructure to identify corridors in need of optimization.
Made Public Date

Performance-Based Operations Assessment of Adaptive Control Implementation in Des Moines, Iowa


While maintaining optimal mobility on signalized intersections is ideal, agencies often face resource constraints that limit their ability to frequently test and revise signal timing at intersections. This study, performed for the Iowa Department of Transportation by the Institute for Transportation at Iowa State University, examines the use of probe vehicle data, such as those provided by INRIX, a commercial traffic data vendor. Such data eliminate the need for installing field infrastructure. Further, many agencies already purchase such data for other uses, or are able to obtain similar sets from commercial vendors or various governmental sources.

The report presented methodology for comparing arterial corridors in terms of mobility-based performance measures, with the goal of establishing a process for easily identifying corridors in need of signal re-timing or adaptive signal control.

The evaluation first identified the number of "abnormal" traffic days in a year to characterize the cost-effectiveness of an adaptive system. Then, for "normal" days, it compared volume-normalized performance among corridors to identify problematic segments. This analysis was performed for a total of 13 arterial corridors: 12 around Des Moines, and 1 in Omaha.

Lessons Learned

The study methodology identified three corridors with high numbers of "anomalous" days, and three that performed poorly on "normal" days.

Researchers characterized the analysis used as "extensible," and considered the available performance metrics from the data to be both "flexible and robust" in accurately identifying problematic corridors.

The study suggested that its methods may be expanded to cost-benefit analyses, to identify agency priorities for arterial improvements, or to effectively automate the process of screening locations for signal re-timing.

Though dollar amounts were not given, as the data used had already been purchased by the Iowa DOT the cost savings incurred by not purchasing and installing field infrastructure were indicated to be considerable.

Goal Areas
System Engineering Elements