On the morning of the 20th at around 8:05 AM, a significant vehicle collision involving 12 cars happened inside the Inaki Tunnel of the Shin-Tomei Expressway in Shinshiro, Aichi Prefecture. According to local police, four individuals aged between 10 and 50 complained of chest pains and were subsequently taken to the hospital, although their injuries were reported as minor.

The police described that the incident began when three passenger cars collided, creating a backup of traffic. Following this initial crash, two more subsequent accidents occurred: one involving six vehicles and another involving three. As a result, severe congestion ensued on the expressway, prompting authorities to close the downwards lane for about four hours, from 8:30 AM to 12:30 PM, particularly between the Shinshiro Interchange and the Okazaki East Interchange.

This incident highlights the hazards of driving in congested conditions, especially within tunnels, where visibility and maneuverability can be limited. Efforts from emergency services were promptly undertaken to ensure the safety and well-being of those involved, and the closure provided a necessary measure to clear the area of wreckage and alleviate further traffic disruptions.