Wheel-detachment crashes cluster in the weeks when drivers switch to winter tires, and Japan's cars still lack a warning system that major overseas markets require on new vehicles. Two cases in Hokkaido in late October followed the pattern.
On the afternoon of October 26, the left front wheel came off a passenger car on a municipal road in Asahikawa, Hokkaido, and struck another vehicle. The driver, a man in his 70s, had changed to winter tires himself that morning, and loose wheel nuts are believed to be the cause.
The next day, on a national road in Otaru, a wheel came off a moving car and hit the wall of a shed. That driver had also changed the tires himself the day before and was on his way to a tire shop to have the nuts retightened. No one was reported hurt in either case.
A 4-year-old hit in Sapporo
In November three years ago, also in Hokkaido, a wheel came off a moving car and struck a girl who was 4 at the time, leaving her with severe head injuries. She remains unconscious.
The car in that crash had been illegally modified. In April 2025, the Sapporo District Court found that loose wheel nuts directly caused the wheel to come off and convicted the driver and the car's owner.
128 large-vehicle cases in a year
The transport ministry reported 128 wheel-detachment crashes involving large vehicles nationwide in fiscal 2025, eight more than the previous year, in material released on October 1. About half fell between November and January, and more than half happened within a month of tires being removed and refitted. More than 90 percent involved the left rear wheel.
No figure is available for crashes involving ordinary passenger cars. The seasonal pattern around the winter tire change is the part every driver should know.
Sensors sold abroad, not in Japan
Technology can catch a loosening wheel nut before it fails, and tire-pressure monitoring systems (TPMS), which warn a driver when a tire loses pressure, are fitted to new cars sold in major countries. In Japan they are not standard, and the article does not say why the systems have not spread here.
The girl's case and the two October crashes point the same way: a wheel that comes off at speed endangers people who never chose to be near the car.