This paper presents the results of biomechanical testing of the SID-IIs beta+-prototype dummy by the Occupant Safety Research Partnership. The purpose of this testing was to evaluate the dummy against its previously established biomechanical response corridors for its critical body regions. The response corridors were scaled from the 50th percentile adult male corridors defined in International Standards Organization Technical Report 9790 to corridors for a 5th percentile adult female, using established International Standards Organization procedures. Tests were performed for the head, neck, shoulder, thorax, abdomen and pelvis regions of the dummy. Testing included drop tests, pendulum impacts and sled tests. The biofidelity of the SID-IIs beta+-prototype was calculated using a weighted biomechanical test response procedure developed by the International Standards Organization. The overall biofidelity rating of the SID-IIs beta+-prototype is 7.0, which corresponds to an International Standards Organization classification of “good”. Also included, are detailed design and instrumentation updates made to the alpha-, beta- and beta+-prototypes of the SID-IIs. Verification test results and updated dummy verification response corridors are also included.