Good for you...wow, that must have been scary...
A couple of years ago, I was on the parkway (and maintaining a safe distance) when the SUV in front of me that had a sheet of plywood on the roof had the plywood fly off and land right on the road in front of me...since I was far enough back, I had plenty of time to safely change lanes to get out of the way...
A few weeks ago, I was on another parkway (and yet again, maintaining a safe distance) when a pickup truck with mattresses hanging off the truck bed had one of the mattresses fly off the back and land right in the middle of the road...again, I was able to safely get away...
A few years ago, my son and his friend were on their way to an amusement park about 100 miles from our house...the friend was driving...they were in the left lane when my son noticed a tractor trailer's gigantic tire right smack dab in the middle of their lane...the friend tried to swerve to avoid the tire and lost control of his car and they slammed head-on into the left lane concrete median...both airbags deployed...
While they were waiting for the police to arrive, they were sitting on the median with their car blocking the entire left lane...
The cop came and asked them if they were ok, and did they need to go to the hospital...(keep in mind they were 18 yr old KIDS that were probably IN SHOCK from the accident)...they said no, so the cop told them to wait there for a tow truck to come, while leaving them ALONE on the median in the left lane by themselves for 30+ minutes until the tow truck finally showed up...

I cannot believe the cop didn't stay with them and direct traffic away from where they were sitting in harm's way on the New Jersey Turnpike, a 6 lane highway with quite a bit of car and truck traffic...yikes!
Also, I think they should have gone to the hospital to be checked out...