This paper includes madymo simulations and sled tests for airbag depowering. A compact vehicle's driver and passenger airbags, developed for previous FMVSS 208 regulation, were depowered 20% and 30%. Sled tests and madymo simulations were performed with the sine sled pulse for baseline and depowered airbags under unbelted condition. The results of simulation were compared with those of sled tests which were conducted according to the procedure of amended regulation. In addition, so-called “ridedown energy” management technique was introduced to improve the understanding of physical differences between sine sled pulse and vehicle barrier pulse.By comparing the sine pulse with barrier pulse of a compact vehicle and a mid sized vehicle, it was found that the sine pulse is a typical body pulse of a large sized vehicle and a compact vehicle pulse normally has shorter vehicle rebound time and higher deceleration peak than sine pulse because of small energy absorbing spaces in engine room. The simulation and sled test results showed that the airbags, which were depowered 20% and 30%, meet most injury criteria of the amended regulation. The HIC value of depowered airbag increased almost twice as much as that of non depowering airbag although the values were not high. Chest acceleration of sled test and simulation based on sine pulse decreased to 60%∼80% of that of barrier test with baseline airbag. Neck injuries were satisfied for all the considered airbags. The ridedown energy level of sine pulse is much higher than that of barrier test because of longer rebound time.