Children and smaller adults will be better protected from inflating air bags under an overhaul of the federal government's standards for the safety equipment, according to Transportation Secretary Rodney Slater. Under a new rule that takes effect with the 2004 model year, automakers will be required to perform tests using an entire "family" of auto dummies, including 1-, 3-, and 6-year-old children and a small woman, as well as an average-sized man. "This rulemaking continues our extensive series of actions designed to preserve the benefits of air bags and decrease the potential hazard for children and small adults," Slater said in a statement. The rule also calls for a 25 mph crash test, which the auto industry promotes as a standard that will protect smaller passengers. Since 1990, air bags have killed 158 children and small adults, most unbelted and involved in low-speed crashes. During a phase-in period between Sept. 1, 2003, and Aug. 31, 2006, vehicles will be required to meet requirements for reducing air bag risks, either by automatically turning off the air bag in the presence of young children or deploying the air bag in a manner much less likely to cause serious or fatal injury, officials said. During a second phase-in from Sept. 1, 2007, to Aug. 31, 2010, the maximum test speed for belted average-size dummies will increase from 30 mph to 35 mph. Transportation officials say the rule could change after a period of public comment and reaction to the slower-speed test.