Side air bags that protect the head, chest and abdomen cut the risk of death in side crashes nearly in half, according to insurance industry research released on September 5. But when the side air bags protect only the torso, not the head, the risk of death is reduced by just 10 percent, says the Insurance Institute for Highway Safety. The institute's study, based on actual crashes in 1997-2002 cars, is the first to estimate the effectiveness of side air bags. It is particularly important now because even though side air bags are increasingly available on new cars, the types of bags offered vary widely. Additionally, many of the side air bags offered are not standard equipment. Of 2003 model-year vehicles, 40 percent offered head-protecting side air bags, but only 24 percent were standard. Some vehicles have separate side air bags for the head — referred to as either curtain or inflatable tube — which inflate from the roof area above the door. Others have head/torso bags that inflate out of the seat or occasionally, the door. Insurance institute president Brian O'Neill says that while head protection has always been important, the increasing number of taller vehicles on the road heightens the risk to car occupants. The institute recently did crash tests of small sport utility vehicles hit by barriers representing larger SUVs or pickups and found the three best-scoring vehicles had head-protecting air bags. More than 9,000 people are killed every year in side-impact crashes.