Impact of COVID-19 on Traffic Signal Systems: Survey of Agency Interventions and Observed Changes in Pedestrian Activity
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work is supported in part by the Utah Department of Transportation (Research Project 18.602).
Transportation Research Record
Traffic monitoring, Real-time information, COVID 19 (Disease) -- United States
The COVID-19 pandemic, the most significant public health crisis since the 1918–1919 influenza epidemic, is the first such event to occur since the development of modern transportation systems in the twentieth century. Many states across the U.S. imposed lockdowns in early spring 2020, which reduced demand for trips of various types and affected transportation systems. In urban areas, the shift resulted in a reduction in traffic volumes and an increase in bicycling and walking in certain land use contexts. This paper seeks to understand the changes occurring at signalized intersections as a result of the lockdown and the ongoing pandemic, as well as the actions taken in response to these impacts. The results of a survey of agency reactions to COVID-19 with respect to traffic signal operations and changes in pedestrian activity during the spring 2020 lockdown using two case study examples in Utah are presented. First, the effects of placing intersections on pedestrian recall (with signage) to stop pedestrians from pushing the pedestrian button are examined. Next, the changes in pedestrian activity at Utah signalized intersections between the first 6 months of both 2019 and 2020 are analyzed and the impact of land use characteristics is explored. Survey results reveal the importance of using technologies such as adaptive systems and automated traffic signal performance measures to drive decisions. While pedestrian pushbutton actuations decreased in response to the implementation of pedestrian recalls, many pedestrians continued to use the pushbutton. Pedestrian activity changes were also largely driven by surrounding land uses. The COVID-19 pandemic, the most significant public health crisis since the 1918 to 1919 influenza epidemic, is the first such event to occur since the development of modern transportation systems in the twentieth century. The first cases in the U.S. were reported in January 2020, and by March cases had spread to all 50 states and the District of Columbia. By the end of March, most states had implemented various stay-at-home policies that closed schools and businesses, with many of these gradually and partially reopening by May. While a gradual return to more normal conditions has been observed, there is still continuing uncertainty as to whether a new round of closures or similar precautions will be necessitated in the future. These events reduced the demand for trips of various types, and the impact on transportation systems has been noted in various early reports. An analysis of probe data by INRIX shows that passenger car travel in the U.S. fell to roughly 60% of ordinary levels before March 2020, slowly recovering after late April to about 90%, with freight traffic seeing a smaller impact (1). Some agencies responded by closing roads to vehicle traffic to prioritize pedestrian and bicycle traffic (2). The reduction in traffic volumes saw a proportionate reduction in motor vehicle crashes (3). Traffic signals are a significant component of the surface roadway system that are generally used at intersections with moderate to high levels of traffic. The substantial reductions in traffic volumes undoubtedly shifted volumes at many signals well away from the conditions that the signal timing was designed for. At the same time, pedestrian use of signalized intersections may have decreased in some areas but increased in others, suggesting a need to adapt signal operations to changing conditions. The recent traffic reductions are a temporary situation, but the traffic engineering community would be remiss not to use the opportunity to learn what sort of policies and other actions are more favorable under such circumstances. A starting point to developing this understanding is to investigate what was done in response to the situation, and to use available resources to quantify the impact. This paper seeks to begin this conversation by presenting results of a survey on agency reaction to COVID-19 with respect to traffic signal operations, and by exploring changes in pedestrian activity during the spring 2020 lockdown. In addition, this paper addresses a case study example in Salt Lake City, Utah, that looked at the effects of placing intersections on pedestrian recall (with signage) with the goal of stopping pedestrians from pushing the pedestrian button. The last section of the paper analyzes the changes in pedestrian activity at signalized intersections in Utah between the first 6 months of both 2019 and 2020 and explores the impact of land use characteristics. The paper concludes with some ideas for future research.
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Singleton, P. A., Taylor, M., Day, C., Poddar, S., Kothuri, S., & Sharma, A. (2021). Impact of COVID-19 on Traffic Signal Systems: Survey of Agency Interventions and Observed Changes in Pedestrian Activity. Transportation Research Record: Journal of the Transportation Research Board, 036119812110263. https://doi.org/10.1177/03611981211026303