WASHINGTON – The National Highway Traffic Safety Administration has adopted new regulations that'll require automakers to equip vehicles with additional front-passenger side-impact protection for the head and torso by 2013, effectively mandating the use of side-impact airbags.

Alongside the new regulations, NHTSA will introduce a new side -impact test that simulates a collision with a narrow object such as a tree or utility pole using a pair of advanced crash-test dummies. One of the dummies is the size of an average size man, while the other is the size of a petite woman. According to the government, 34 percent of serious and fatal injuries in side-impact tests are suffered by occupants under 5'4" in height.

Side-impact crashes account for 28 percent of fatalities, with most involving some degree of brain injury. The NHTSA estimates that the risk of death drops by 24 percent in vehicles equipped with head and torso side-impact airbags, with torso airbags alone dropping the risk by 14 percent. The new requirements should save nearly 300 lives a year while preventing nearly 400 serious injuries.

Side impact airbags are already a common feature thanks to a voluntary agreement between automakers to phase in the technology. Nearly every vehicle on the market today is sold with side-impact airbags as a standard feature or as a relatively inexpensive option.