The date and time shown in the video are incorrect. The accident reportedly happened on Thursday June 27, 2013 at around 10:15 am. A commuter van covering the route between Surabaya and Tuban in East Java, Indonesia rear ended a trailer parked on the side of the road in the village of Sukodadi in Lamongan regency. The van driver probably dosed off for a second, which was enough to cause the tragedy.
Three people died instantly as van got crushed under the trailer, one was critically wounded but died as well, later in a hospital. Considering that this was filmed in Indonesia, the video is strangely not of horrible quality.
One more video (less interesting) of the same accident aftermath:
Bonus video also from Indonesia, unrelated to the above accident. Filmed sideways, shows three victims of some other accident I got no background info about: