New Video Shows Moment NYC Worker Ran Over, Decapitated Elderly Man

New video from the horrific scene where a city truck decapitated an elderly man in New York shows the moment the vehicle made contact ... and shockingly, it happened slowly.

Surveillance footage going around online catches the 86-year-old victim slowly making his way across a street in Brooklyn ... and he actually narrowly avoided another car that took a left turn just as he was starting to cross -- before the NYC Dept. of Transportation truck arrived.

The elderly man waits for that car to pass before continuing across the street ... when the big yellow Transportation truck starts to turn right, heading directly into his path and hitting him.

It's almost as if it all unfolds in slow-motion -- and it seems the truck driver didn't even see the old man, because it didn't slow down, nor did it stop once it struck the guy. Instead, the vehicle just rolls right over him ... and leaves the body behind in the aftermath.

In this clip, you don't clearly see the decapitation -- but we know this poor man's head was severed as a result of the accident based on other footage that surfaced showing the scene.

A man in a work vest -- who is presumably the driver in this tragedy -- was also filmed kneeling and buckling on the ground afterward ... looking absolutely devastated.