Reminder: Shoulder it on sudden stops.

[NYC_SKP]

1. Interest to read the comments.

Without doubt, the truck was at fault.

However, had the bikes ahead not been pulled over in that 17 inch strip of pavement right with a steep grade dropping off the shoulder, the Nissan wouldn't have stopped and the truck wouldn't have had a dead object in the middle of the street to ram into.

Were I in the Nissan, I'd likely have slowed but not stopped.

So there are some contributors to what happened here: the bikes ahead, the Nissan, but more than anything the truck driver who, as suggested in the comments, might well have been texting or reading emails.

Damn.