Runge raised the ire of auto industry giants last month when he said in a speech in Dearborn, Mich., he would not allow his children to drive an SUV because of safety issues.
The former emergency room physician softened his criticism of the industry but said the government was ready to legislate safety improvements if the industry failed to tackle the problems of rollovers and bumper incompatibility of ever bigger, heavier SUVs with smaller vehicles.
"I bet they get there before we get there," Runge told the Senate Committee on Commerce, Science and Transportation. "We will be moving in parallel and we will be watching them closely. Hopefully it can be done without huge regulation."
The Alliance of Automobile Manufacturers Tuesday said SUVs were just as safe as cars and that SUVs were safer in side, rear and frontal collisions, about 97 percent of all crashes. Both Runge and the automakers said all occupants would be safer if they simply buckled their seat belts.
Seventy-two percent of SUV rollover fatalities involved people not wearing seat belts.
Joan Claybrook, president of the consumer group Public Citizen, said voluntary industry agreements to improve fuel economy and design safety are less effective than mandated standards.
"Manufacturers have known for years about these hazards," said the former NHTSA administrator, "and instead of acting voluntarily, have bobbed, weaved, delayed and denied."
Toyota said anti-lock brakes, stability control, side airbags, crumple zones and front cross beams had all improved motor vehicle safety, adding Toyota is ahead of schedule in meeting voluntary industry guidelines.
Runge said SUVs were three times as likely to rollover in some accidents. There are about 79 million SUVs, minivans and light trucks on U.S. roads, about 36 percent of all vehicles and light trucks outsold cars for the second year in 2002.
More than 42,000 people died in highway crashes in 2001 -- 8,400 in single vehicle rollovers -- and more than 3 million were injured.
"While the overall fleet is safer," said Runge, "the new fleet composition presents new safety issues. Two issues stand out. Rollover is one issue. Pickups and SUVs are involved in a higher percentage of rollovers than passenger cars -- the rate of fatal rollovers for pickups is twice that of passenger cars and the rate for SUVs is almost three times the passenger car rate."