Dozens more were injured when the vehicle collided with a line of waiting cars in Lanzhou, the provincial capital of Gansu, on Saturday.
The cause of the 31 vehicle pile-up is under investigation.
However, according to China's Xinhua news, the lorry driver told authorities his brakes failed as he travelled down a hill towards the toll station.
Xinhua puts the death toll at 15, with another 44 people injured.
Source:
BBC