The Transportation Department says the new requirements are aimed at protecting motorists in rollovers. More than 8,000 people were killed in rollovers in 2009, according to the most recent data available.
The new requirements are the latest attempt to address such crashes. The Bush administration required car companies to put anti-rollover technology called Electronic Stability Control on new vehicles.
The changes to the air bags are expected to prevent nearly 400 deaths and nearly 500 serious injuries every year.
Car companies will begin phasing in the changes in 2013 and all new cars will be required to have the protections by 2018.