This study uses an existing database of dynamic loading tests of driven piles installed in the Puget Sound Lowlands to improve the reliability of axial performance. First, the unit shaft resistances developed from stress wave signal matching to dynamic records of pile installation are used to develop an effective stress-based shaft resistance model. New, statistically unbiased unit shaft resistance models are proposed for piles driven at End-of-Drive (EOD) and Beginning-of-Restrike (BOR) and for a range of specific soil types and relative densities and consistencies. The accuracy and uncertainty of each model is quantified and compared. Then, the observed unit shaft resistances and proposed design models are used to characterize the magnitude of time-dependent capacity gain. Although these models allow estimation of the range of capacity gain anticipated following pile installation, no reliable time-dependent relationship could be proposed. The study concludes with the quantification of accuracy and uncertainty in dynamic wave equation-based and existing static analysis procedures and calibration of resistance factors for use with load and resistance factor design (LRFD). These resistance factors indicate, in some cases, dramatic improvement in the useable pile capacity at a given reliability owing to the use of a database from a specific region. The results from this work may be immediately applied in practice in the Puget Sound Lowlands.