Understanding changes in traffic conditions during the Tokyo 2020 Olympic and Paralympic Games

We investigate changes in traffic conditions during the Tokyo 2020 Olympic and Paralympic Games. Given the network topological advantages of the Tokyo Metropolitan area, where most tolled expressways and highways are parallel, the expressways were primarily used for transporting the Olympic families by implementing TDM strategies during the Games. According to Tokyo Metropolitan Government (2021), the daily total trips on the Tokyo Metropolitan expressways decreased by approximately 12 % compared to one week before the Games. However, the temporal changes on traffic conditions have not been fully investigated. To address this gap, we evaluate temporal patterns using the Macroscopic Fundamental Diagram (MFD), estimated from multiple data sources. Additionally, we develop an anomaly detection approach to identify and analyze changes in highway traffic congestion resulting from the TDM strategies implemented during the Games. We find that the expressway traffic conditions were moderately managed at the aggregate level. Moreover, highway traffic congestion patterns did not change significantly during the Games, but several unusual patterns are identified by the anomaly detection approach. We discuss potential reasons for these observations, including the possibility that expressway congestion induced by the TDM strategies contributed to speed reductions on the highways. • Investigate changes in traffic conditions during the Tokyo 2020 Olympic Games • Evaluate temporal patterns using MFDs estimated from multiple data sources. • Develop an anomaly detection approach to identify unusual traffic patterns. • Expressway traffic conditions were moderately controlled at an aggregated level. • Several unusual patterns emerged on the highways.