Bolivia has a sorry record when it comes to highway safety, and crashes involving buses travelling at night are common.
A bus missed a curve on a road near Bolivia's capital on Friday and plunged down a ravine, killing at least 14 people and injuring 19 more, officials said.
Local fire department chief Ismael Villca told Erbol radio that the bus had left the capital half an hour earlier en route to the northern town of Coripata.
It was the third serious accident of the week in Bolivia.
A small bus collided with a cargo truck on Tuesday, killing 14 people west of La Paz, while a bus and truck collided on a road to the Uyuni salt flats in southwestern Bolivia, killing three.
Road accidents in Bolivia are frequent and, according to a police report, are mainly due to poor visibility, irresponsibility of drivers and consumption of alcoholic beverages.
Thirty-one deaths have been reported this week as a consequence of road accidents in Bolivia.