This report details the critical updates to the Strategic Highway Research Program falling weight deflectometer (FWD) calibration procedure. This has led to the revision of the American Association of State Highway and Transportation Officials R32-09 calibration procedure. The report describes the procedural improvements and provides information on how to calibrate an FWD according to the updated procedure. Appendices provide the updated protocol for FWD calibration, drawings and specifications of the hardware needed, an updated specification for the pavement deflection data exchange (PDDX) protocol, and a flowchart for the new calibration software, WinFWDCal. This report will be of interest to engineers who perform structural evaluation of pavements.