An overloaded car, driving with illness and failing to repair a known brake problem has been ruled as the cause of the serious road accident that occurred in northwest China's Gansu province earlier this month, according to a local government report.

15 people were killed and 44 others injured in the 31-vehicle pile-up at the Lanzhou South toll station on the Lanzhou-Haikou Expressway in Lanzhou, capital of northwest China's Gansu province, on November 3, 2018.