Sasago Tunnel

The Sasago Tunnel (笹子トンネル) is a twin-bore motorway tunnel on the Chūō Expressway located on the border of the cities of Kōshū and Ōtsuki in Yamanashi Prefecture, Japan. It is located about 80 km west of the capital Tokyo. It was built in 1977.

Ceiling collapse
At approximately 8 am on December 2, 2012, nearly 150 concrete ceiling panels inside the Tokyo-bound Sasago Tunnel collapsed, crushing three vehicles, including a van, carrying six persons, that caught fire. The fallen panels were 20 cm thick and weighed 1.2 t each. The caved-in point was 2 km from the Tokyo-side exit and spanned a length of 50 to 60 m. Smoke could be seen billowing from the Kōshū entrance to the tunnel.

Nine people died and two were injured, making it the deadliest roadway accident in Japanese history. The tunnel was closed for a period of 27 days for repairs and removal of ceiling panels, before the south tube reopened on December 29. The north tube, where the collapse happened, reopened on February 8, 2013.

The nature of the collapse closely resembled a similar ceiling collapse in the Fort Point Channel Tunnel in Boston, Massachusetts in 2006.