"We do some work on primary state routes (3,500 to 6,000 vehicles a day), but it really is ideal for some of our farm roads that might only carry 50 to 100 vehicles, or even 500 vehicles a day," McCarter says. "On the heavily traveled roads we generally apply a hot mix overlay, but on the rural roads with lighter traffic volumes, the chip seal is a more economical approach, and if increased traffic volume warrants it, we can always come back and apply a hot mix overlay."

While the number of lane miles targeted for FDR varies from year to year, McCarter says that when 15 to 25 percent of a designated road requires full-depth patching, it generally becomes a candidate for the FDR process.

"We have some roads, especially in York County, which is becoming more populated, that are deteriorating rapidly, and we're finding that FDR is a good way to bring those roads back and provide a stronger base for future improvements," McCarter says. "If we can also wait a few years after chip sealing an FDR road, it gives us some time to see if any other structural problems show up, and then we can fix those problems before we apply a hot mix overlay."