THE REAL MISTAKE:
The van driver failed to drive straight into the intersection. As can be seen in the video, the van is pointed left, even before it begins its turn. Vehicles run red lights all the time, and had the van proceeded straight into the intersection, checked for oncoming traffic before turning, it would have waited for the truck, and there would have been minimal danger of the truck running the red light.
One person commented that waiting to turn left in an intersection is illegal - it is not illegal.
And there are 2 schools of thinking on the correct procedure for turning left.
wait with the steer tires on the front crosswalk line - that way the vehicle is not in the intersection, but is committed to the turn and can move through the intersection on the amber.
move as far forward in the intersection as possible so that when the light changes to amber, as many vehicles as possible can clear the intersection.
If a vehicle is in the intersection when the light turns amber, that vehicle owns the intersection and must quickly, efficiently, and safely clear the intersection.
As well, if you watch the video carefully, you can see—as most drivers do—the van’s driver inches forward as the light gets closer to amber. When the light turns to amber, the driver begins to move left through the intersection without properly checking oncoming traffic before proceeding.
The "inching forward" is part of social driving that sees drivers begin to be pressured by other traffic on the roadway. If the vehicle turning left is still in the intersection when the light changes to red, most drivers percieve themselves as blocking the intersection and holding up other traffic. Consequently, the driver feels pressured, and often makes mistakes - as the driver did in this video.