I read through most of this thread after finding it through a frantic Google search. I guess I'm responding in a way to try to help. This is so horrific my response is almost compulsory, and yet I'm so sad that nothing I can do will bring this victim back.
I'm not comfortable disclosing my identity or proximity to the accident but suffice to say that it's as close as one could get, while not being the driver of the dump truck.
Foremostly I want to offer my deepest condolences to the victims family and community. The owner of the Tesla was apparently on his way to the airport to pick up family for the holidays, truly gut wrenching. There simply are no words.
The Dump truck was not affixed with a blade of any sort. It was simply used to transport snow and dump it. It was also a privately owned truck. It was traveling northbound when the driver lost control, the driver regained control over the truck just prior to the intersection as the light turned red. He then made the fatal decision to proceed through the intersection rather than slide through with all the brakes on again losing control. The driver of the Tesla was westbound out the outside lane. The inside lane was occupied by a tractor trailer, blocking the view of the danger that was coming broadside. The dump truck was moving at approximately 65 km/h (not mph) when it struck the Tesla. I am not able to say whether the driver of the Tesla had "timed" the green light or started from a dead stop. As you know the cars acceleration is not like any other and despite the light having just turned green the car may have been at a dead stop. The dump trucks nose was squared right on the drivers side doors.
The emergency crews did cut the entire car apart to get the victim out but to no avail. I feel ill still. My only hope is that the driver of the dumptruck takes responsibility for his actions. Obviously not intentional, but his choice has changed many lives forever.