This document summarizes airbags as a safety restraint system in automobiles. It discusses how airbags were developed as an improvement over seat belts alone. The main parts of an airbag system are identified as the bag, sensor, and inflation system. Airbag sensors use either mechanical crash sensors like a ball-in-tube or spring mass sensor to detect impacts and trigger inflation of the gas-filled airbag cushion. The document concludes by discussing future smart restraint systems and how drivers can check the functioning of their airbag system.