In fact, the very figures on scrap tire utilization vary from year to year, thanks to the vagaries of scrap tire generation, according to Sheerin.
In 2017, for example, 81.4 percent of the scrap tires generated in the U.S. reached end-use markets. This compares with 95 percent in 2013 and 87.9 percent in 2015.
But this decrease, Sheerin said, mostly is due to the constant increase in scrap tire generation. In 2017, it grew 4 percent to 4.19 million tons, according to the report.
TDF was the largest market for scrap tires in 2017, accounting for 43 percent of the total, the report said. Economic factors have created a drop in TDF demand, but also creates promise for the future in that market, Sheerin said.
TDF demand in the pulp and paper industry fell with decreasing demand from newspaper and magazine publishers, he said. In utilities, TDF must compete with low-cost natural gas.
On the other hand, the demand for TDF in cement kilns is growing steadily.
"Demand in the construction market has been very strong," Sheerin said. "The cement industry is using more TDF than ever before."
Similarly, changes in rubberized asphalt technology and within state highway departments are helping that material gain acceptance, according to Sheerin.
For decades, rubberized asphalt suffered a bad reputation because of the Intermodal Surface Transportation Efficiency Act in the early 1990s.
A provision of ISTEA required the states to use an ever-increasing amount of rubberized asphalt in their road projects as a condition of receiving federal funds.