airbag

An airbag is a vehicle occupant restraint consisting of a flexible fabric bag that inflates rapidly during a collision to cushion the occupant. It is part of a supplemental restraint system that works with seat belts to reduce injuries.

Airbags deploy when crash sensors detect a rapid deceleration or impact. In most systems, a gas inflator generates gas (typically nitrogen) to fill the bag within milliseconds, allowing it to emerge from steering wheels, dashboards, or other panels. The bag then deflates quickly to permit movement after cushioning. Modern systems use multi-stage inflators and occupancy sensing to tailor deployment to crash severity and occupant size. Common configurations include frontal airbags for drivers and front passengers, knee airbags, side torso airbags, and curtain or roof airbags.

History and development: modern automotive airbags began to be adopted in the late 20th century and became widespread in the 1980s and 1990s, expanding from luxury models to many vehicles as standard equipment.

Safety considerations and limitations: airbags are designed to work with seat belts and can cause injury if occupants are seated improperly or very close to the bag, particularly for children. Children under 13 should ride in the rear seats; infants require appropriate restraints. Airbags are not a substitute for safe driving, braking, or seat belt use, and they may not deploy in all crashes or in all seating positions.

Regulation and maintenance: airbags are evaluated under standards such as FMVSS 208 and FMVSS 214 in the United States and corresponding UNECE regulations elsewhere. After deployment, replacement and system inspection by qualified technicians are required. Warning indicators signal faults in the airbag system.