U.S. safety investigators, concerned about rollover crashes, have asked regulators as well as General Motors Corp. and Ford Motor Co. to take steps to improve the safety of 15-passenger vans.
The National Transportation Safety Board wrote to the chief executives of both companies Friday, recommending the manufacturers look into technology that would help drivers maintain better control of these vehicles.
"The safety board is vitally interested in this recommendation because it is designed to prevent accidents and save lives," said Carol Carmody, the board's acting chairwoman, in a letter to Ford Chairman William Clay Ford Jr. and Rick Wagoner, GM's president.
In a separate letter, the safety board urged the National Highway Traffic Safety Administration to include 15-passenger vans in its enhanced rating system for measuring rollover risk.
Regulators are developing a road test to determine rollover propensity, which is now based on vehicle measurements. That system will rate cars and light trucks, which include pickups, sport utility vehicles and minivans.
"We'll certainly consider it," said NHTSA spokesman Rae Tyson. "Anytime the NTSB sends a recommendation we'll consider it seriously."
The safety board has no regulatory authority.
Fifteen-passenger vans are typically used by community groups for short trips as well as by colleges for their athletic teams and student organizations. Vanpools also use them for commuters.
According to highway safety data, large vans are involved in a higher number of single-vehicle accidents involving rollovers than are other passenger vehicles.
There are about 500,000 15-passenger vans on the road, and at least 424 people have been killed and hundreds of others hurt in rollover crashes involving these vehicles since 1990, highway traffic figures show.
Two NHTSA advisories in the last two years, prompted by high-profile crashes, have warned consumers about the increased rollover risk of 15-passenger vans in certain conditions.
Rollover risk is heightened if the vehicle is fully loaded or nearly full. Safety experts also say their extended length, a higher center of gravity and restricted handling capabilities can make them vulnerable to rollover.
Ford builds the most 15-passenger vans. GM has only a small fraction of the market. Because of a difference in design, the GM vans are involved in fewer rollovers than those made by other manufacturers.
Ford spokeswoman Carolyn Brown said the automaker stood behind the safety of its product but said the operating manual for vans includes warnings about overloading and driving the vehicle at high speeds.
GM also backed the safety of its 15-seat vans. Mike Morrissey, a spokesman for the company, said GM welcomed the safety board's recommendation as a "constructive suggestion."
The safety board recommended that automakers consider a range of technologies to give drivers more control of 15-passenger vans. These include traction-control features, devices that warn drivers when they suddenly leave a traffic lane, and computer systems that can brake individual wheels or adjust power to enhance steering control.