The reason is still unknown. Some speculate that it was due to a aftershock from an earthquake a few days prior. Some say it is due to bad construction practices. Regardless of why it happened, the pictures show the impact on the highway. The hole is about 40 feet deep and 200 feet long.
Luckily no one got hurt when this happened. Notice that some of the orange traffic drums are not tipped over.
VIEW FROM THE SKY
Photos from Facebook posted by Protección Civil, Cavaro Comunicación, and passersby.