Two buses collided on a winding road in the Bolivian altiplano early on Saturday morning, killing 22 and injuring 37, authorities said. Police said later in the day that the two buses hit head-on, crushing the front ends of both vehicles. They said the crash happened along the road that connects Oruro and Potosi, both high altitude cities above 12,000 feet (3,657 meters). Several of the injured had been transferred to local hospitals, according to police reports. Such bus accidents have become increasingly common in Bolivia. Many of the country´s roads, including those that drop down from the capital city of La Paz, are carved from steep slopes of the high Andes mountains and are known to be treacherous.