A study of frontal collisions using the NASS data base showed that there were four times as many arm injuries to belt restrained drivers who had an air bag deploy than for the drivers who were simply belted. By far, the distal forearm/hand was the most commonly injured region. Hard copy review identified two modes of arm injury related to the deploying air bag:​ 1) The arm is directly contacted by the air bag module and/or flap cover, and 2) The arm is flung away and contacts an interior car surface.Based on the field studies, a mechanical device called the Research Arm Injury Device (RAID) was fabricated to assess the aggressivity of air bags from different manufacturers.Results from static air bag deployment tests with the RAID suggested that the RAID was able to clearly distinguish between the aggressive and non-aggressive air bags. Maximum moments ranging between 100 Nm and 650 Nm, and hand fling velocity ranging between 30 and 120 km/h were measured on the RAID in these tests. In general, the aggressive air bags imparted a maximum moment on the RAID above 300 Nm and a hand fling velocity above 70 km/h.Two factors were identified as critical to the test setup. The first was the orientation of the arm with respect to the air bag module. The second was the distance of the arm from the plane of the air bag module face. The maximum moment and fling velocity increased when the initial distance between the RAID and the air bag module was reduced.