Apparently, it was a piece of plastic (I'm thinking part of a garbage bag). Here is the tweet that accompanied the pic:
"Pic of our camera's screen. FBI evidence collectors appeared to zero in on piece of plastic in road"
From: https://twitter.com/twoodard8
I think that a poster's suggestion that we figure size of the object based on the aggregate in the road.
I walk on a road similar to that and tonight, if no one else does anything before then, I will do a measurement.
I go with my hubby, SIL and daughter. Ugh.
I hope I can stand them getting all over my case.
My one granddaughter goes to middle school in the fall and the bus will let her off about a mile from home on country roads with no sidewalk and barely any houses.
This will be good review for my daughter to know that there must be another option made. We leave the US for several months, so we are not an option.