• High RAP content mixes can provide excellent rutting performance and durability.  Field performance to date does not indicate that using a softer virgin binder grade improves performance for high RAP content mixes.
• Warm mix asphalt (WMA) placed into service immediately after construction has not exhibited susceptibility to early rutting.  The long-term durability and rutting performance of WMA has been found to be comparable to hot-mix.
• Fine-graded Superpave mixes can perform as well as coarse-graded mixes under heavy traffic.  Fine-graded mixes tend to be easier to compact, less prone to segregation and less permeable.
• The practice of binder grade bumping significantly improves rutting performance of asphalt surface courses.  On average, going from a PG 64 to a PG 76 reduced rutting by 50 percent.  Furthermore, increasing the asphalt content of mixes with modified binders by 0.5 percent did not alter rutting resistance.
• For mixtures with modified binders, low lab-compacted air voids is not a good indicator of rutting.  However, for mixtures with unmodified binders, a strong relationship was observed between low lab-compacted air voids and rutting performance.
• Instrumented structural sections were used to develop fatigue performance models for thick and thin pavements.  These fatigue models can be used with mechanistic-empirical pavement design methods for the design of perpetual pavements.
• Measured strain levels at the bottom of the asphalt layers correlate well with theoretical layered elastic models for a wide range of pavement materials and thicknesses.
• Methods were developed to characterize the fatigue endurance limits of asphalt mixtures in the field.  These endurance limits were considerably higher than those obtained from laboratory testing.
• Excellent performance of SMA test sections has led several states to use this mix type as a premium mix for heavy traffic highways.  SMA with crushed gravel aggregate was also proven viable.
• New-generation open-graded friction course mixes (also known as porous friction courses) have proven their durability.  These surface mixes can eliminate water spray, improve skid resistance, and significantly reduce tire-pavement noise.
• Based upon the success of gravel SMA, open-graded friction course was produced with crushed gravel and was found to exhibit good rutting and drainability performance.
• Several state DOT sponsors have used the NCAT Pavement Test Track to study aggregate quality specifications in order to open up hot-mix markets to more competition.  In this manner, construction costs can be reduced without compromising quality.
• A laboratory method intended to identify mixes that exhibit increased susceptibility to surface cracking was tested and validated.

The performance of various test sections has supported and confirmed numerous other important research projects, including refinement of gyratory compaction levels, evaluation of GPR for estimating in-place HMA properties, refinement of 4.75 mm mix design specifications, development of simple performance tests for HMA, tire-pavement noise studies, development of a field permeability test, correlation of fine aggregate angularity and rutting performance, and refinement of MEPDG performance models.