Severe traffic congestion and train overcrowding peaked across Japan during the latter half of the Golden Week holiday period starting May 2 [1].

This surge in travel demand tests the nation's transport infrastructure and public safety, particularly as unusually high temperatures create additional stress for travelers and operators.

Major highways nationwide experienced significant delays, with some sections seeing travel times more than three times the normal duration [1]. The Chuo Expressway near the Danogasaki Service Area in Yamanashi was among the hardest hit. In that area, it took approximately 20 minutes just to enter the service area due to the surrounding jam [1].

Predictions from NEXCO and the Japan Road Traffic Information Center indicated that highway traffic jams would reach lengths of up to 45 km [2], [3]. These delays were compounded by a heat wave that produced consecutive "summer-day" temperatures, which further intensified the congestion [1].

Rail travel faced similar pressures. On the Hokuriku Shinkansen route from Tokyo, free-seat occupancy reached a maximum of 150% [1]. This level of overcrowding forced many passengers to stand or seek alternative arrangements as they traveled toward their destinations.

The congestion affected a wide range of travelers, including families returning to regions such as Yamagata [1]. The combination of limited road capacity and the timing of the holiday's latter half created a bottleneck for those attempting to return home or reach final vacation spots.

Highway traffic jams were predicted to reach up to 45 km in length.

The convergence of peak holiday travel and extreme weather underscores the vulnerability of Japan's transit corridors. When high-volume periods like Golden Week coincide with heat waves, the resulting systemic stress increases the risk of heat-related health emergencies and operational failures in transport hubs.