Side airbags are mostly installed in the side of the seats. Some are installed in other adjacent places. During a side collision, the side airbag inflates between the door panel and the passenger and helps minimize passenger chest and abdomen injuries. Since the distance between the intruding door and the occupant is so small the inflation speed of the side airbag is the fastest among the various types of airbags.
Side Airbag Deployment Videos
Slow Motion Deployment of Actual Airbag
Slow Motion in-car Simulation