Development and evaluation of a portable crowd-estimation system using Wi-Fi

The real-time monitoring of crowd size is essential for accurate and efficient evacuation guidance and other disaster response efforts in large-scale events. Hence, we developed a portable and cost-effective crowd monitoring system with environmentally friendly features, including waterproofing and dustproofing, using Wi-Fi technology. This system can cope with media access control (MAC) address randomization in detected Wi-Fi devices to enhance headcount detection accuracy. To assess the precision of this method in crowd size estimation, we conducted comparative experiments at the large-scale event "Gorokuichi" in 2021 and 2022. The mean absolute percentage error was 5.86% in 2021 and 8.56% in 2022, demonstrating high consistency, with correlations exceeding 80% between the estimated numbers and human observer counts (true values), thus confirming the effectiveness of our system.