Dive summary:

• Anecdotal evidence that recycled tire rubber makes a good asphalt binder may work in the private sector, but public agencies are reluctant to buy in without hard data from respected tests, even if recycled rubber is a better economic proposition than polymer binders.
• Now, a study by the Rubberized Asphalt Foundation has shown that it's possible to establish a test regimen that accommodates the different particle sizes of recycled tire rubber (RTR) and get dependable and comparable results.
• "Direct comparisons of test results "demonstrates that RTR can be used in place of or in combination with polymer to provide a high-quality performance graded, (PG) binder," the report stated.

From the article:

These issues make highway agencies very reluctant to try RTR technology. ...