LIMA, Peru — At least 44 people died and 20 others were injured in southern Peru on Wednesday when a passenger bus fell off a cliff on the nation’s most important highway — the second such bus accident this year on the notoriously dangerous road.

The two accidents prompted outrage here that the authorities are not doing enough to prevent such episodes despite their frequency and the loss of life involved. In January, 51 people died when a bus plunged off a cliff along a foggy stretch of road so infamous it is known as the “devil’s curve.”

Both accidents occurred on the Pan-American Highway, which stretches the length of the country parallel to the Pacific Ocean. Despite its importance, the vast majority of the road is narrow, with a single lane going each way as it meanders through the Andean hills.