Nebraska Department of Transportation
Anuj Sharmaanujs@iastate.edu email >
Research Scientist and Leader, REACTOR
About the research
As Adaptive Traffic Control (ATC) is increasingly being implemented by various traffic agencies, careful evaluation is needed of the degree to which a given ATC implementation improves traffic signal performance. The present study details the evaluation of ATC for two arterial corridors in the City of Omaha, Nebraska. Several performance measures were used across two stages of ATC implementation as well as during the unanticipated COVID-19 lockdown stage.
The average travel time and variability in travel time showed that Stage 1 of ATC implementation in Omaha did not improve traffic signal performance for the study’s main corridor, Dodge Street. This led to Stage 2 ATC implementation, in which there were slight improvements compared to Stage 1. However, travel time was still found to be higher as compared to the base scenario, though this increase was in most cases within 10%. The city shut down ATC operation during the PM peak period on the Dodge Street Corridor because of its poor performance. ATC was also found to negatively impact side-street delay in most scenarios. However, Omaha’s ATC implementation successfully reduced and adjusted signal cycle length in response to COVID-related demand changes thus showing some responsiveness to changing demand.
In essence, the ACT system does provide adjustments during atypical conditions but cannot outperform static timing patterns during recurring traffic demand.