Try state DOT's - if they have been developing the source data for advanced Mechanistic-Empirical (M-E) design, which should now be rapidly accelerating as it can save significant amounts of asphaltic material by more closely understanding the elastic vs. viscous responses of PG+ polymer modified binder. This tightens up variability so safety factors are typically increased for the same pavement sections.
If that's not what you're looking for, it's an extension thereof, and should be strongly considered in terms of cost effectiveness of flexible vs. rigid pavements.