https://www.youtube.com/watch?v=82FjTM3Rf1U

Ten years ago the gigantic concrete ceiling panels of Sasagi road tunnel in Otsuki, Yamanashi Prefecture has collapsed. It was on 2 December 2012.

The metal parts holding giant concrete ceiling walls failed is reason. They crashed the 3 vehicles (a cold transport truck, a transporter and a saloon car) traveling and started fire. 9 People died in horrific conditions, Sasago Tunnel in central Japan was part of Chuo Expressway maintained by NEXCO Central.

This is simulation how it happen: