The video is of an accident that happened in the city of Cartago in Costa Rica. According to the info I got, a group of party goers crashed the vehicle after taking a U-turn on a highway while returning from the party at 5am.
During the U-turn maneuver, they reportedly cut in front of an oncoming dump truck and got slammed. Looks like they are all dead, and one of them looks to be a child.
Many thanks to Andrey J. for the video: