A woman and her two children were killed in a car pileup involving seven vehicles in Kudamatsu, Yamaguchi Prefecture, on Tuesday as traffic jams caused havoc on the nation's roads.

According to the prefectural police and firefighters, a truck slammed into backed-up traffic on the outbound lane of the Sanyo Expressway at around 9:40 p.m. on Tuesday, not long after a roadblock from a previous crash had been removed. The accident killed a 37-year-old mother, Asami Nakai, from the city of Yamaguchi, her 13-year-old son Shugo and her 9-year-old daughter Maon.

Six other people were taken to hospital with injuries. Two, including a baby, were seriously wounded. The injured were mostly aged in their 30s to 50s.

Police said they were investigating the female truck driver in connection with the crash.

A little after 2 a.m. on Wednesday, two wrecked vehicles from the crash — an overturned car and another — could be seen on the road blocking a lane. Their bumpers were significantly damaged and a door had come off one of the cars.

The outbound lane of the Sanyo Expressway closed for about six hours between Kumage interchange and Tokuyamahigashi interchange as a result of the crash. The roadblock was removed after 4 a.m.