Over 2.04 Million Private Vehicles at Risk in Nankai Trough Megaquake – More Than 5 Times the Scale of the Great East Japan Earthquake

The Japan Carsharing Association (Ishinomaki City, Miyagi Prefecture; Representative Director: Takehiko Yoshizawa) has conducted an original estimation on the scale of private vehicle damage in the Nankai Trough megaquake and the required volume of vehicle support during disasters, based on public statistics and municipal data.

This estimation references the methodology used by the Cabinet Office (Disaster Management) during the Great East Japan Earthquake (number of flooded households × vehicle ownership rate). As a result, it is estimated that over 2.04 million private vehicles could be affected by the Nankai Trough megaquake—more than five times the approximately 408,000 vehicles damaged in the Great East Japan Earthquake.

Additionally, based on the association’s past vehicle lending support performance (approximately 1% of total disaster impact), the required vehicle support is estimated at around 20,000 units, with annual costs of approximately ¥2.6 billion and a total of ¥7.7 billion over three years.

While widespread flooding due to tsunamis is anticipated in the Nankai Trough megaquake, there is currently no official, unified estimate for vehicle damage. Meanwhile, in past disasters, losing a vehicle has significantly hindered commuting, medical visits, shopping, and administrative procedures—impeding recovery.

This estimation aims to visualize the critical issue of 'loss of mobility' and clarify the scale of vehicle support needed during disasters. It should be noted that this is a rough estimate based on certain assumptions, and actual damage and support needs may vary depending on disaster conditions.

Based on these findings, the association proposes the following four measures to the national government and local authorities: ① official assessment of vehicle damage in disasters, ② recognizing 'mobility loss' as a key disaster management issue, ③ institutionalizing vehicle support programs, and ④ establishing systems for utilizing public vehicles during emergencies.

In parallel, ahead of its 15th anniversary in July 2026, the association will advance the strengthening of societal disaster preparedness through initiatives such as the '1,500 Preparedness Partners Challenge,' the '1,000 Locations for Car Donation Posters Challenge,' and the '¥5 Million Crowdfunding Challenge.'

About the Japan Carsharing Association

A nonprofit organization established in Ishinomaki City, Miyagi Prefecture, following the Great East Japan Earthquake. It conducts social contribution activities, including disaster relief support using vehicles donated from across Japan. To date, it has responded to 34 disasters, providing over 10,000 free vehicle rentals. Approximately 2,400 vehicles have been donated. The association is building a nationwide vehicle support network in collaboration with companies and local governments.