When I use to drive a tractor trailer and another trucker saw a big piece of 'retread' that was laying in the road, they would warn you on the CB... And we called the retreads "alligators."
Yea those big pieces of truck tires laying in the roads are from "retreads."
Retreads are called Road Alligators for good reason | NowPublic Photo Archives
I have been doing abunch of reading and this seems to be a common comment.
the rubber along side the road is from tires that have failed, primarily due to underinflation or overloading. As shown in study after study, tire debris on the roadside is made up of both new tire and retread tires in proportion to their usage