DETROIT -- Four-point seat belts will be ready for production by the end of the decade, Ford Motor Co. says.

But despite the promise of the new technology, the automaker won't yet say whether it will install the seat belts in its own production cars.

"We'll put no safety system in our vehicles before it's ready," says Stephen Rouhana, senior technical leader in Ford's safety research and advanced-engineering group. "We don't want to hurt people. So we have to do the homework and due care to make sure it's not going to hurt people. It takes time."

Two issues yet to be addressed are adapting the new design for use by pregnant women and then changing federal standards, Rouhana says. Current standards now count four-point belts as illegal, he says.

Once four-point belts are approved and perfected, Ford anticipates widespread consumer acceptance.

A design tested at many consumer clinics disputes the once-held notion that people would reject four-point belts because of perceived discomfort, Rouhana said. After trying the design, between 75 and 80 percent of people told Ford they would prefer a four-point belt over a three-point belt in their next vehicle.

Ford has been developing the belts since the beginning of this decade. It is working with TRW Automotive Inc., of Livonia, Mich., on the four-point belt and with Key Safety Systems Inc., of Sterling Heights, Mich., on the inflatable belt.

An inflatable seat belt for rear seat passengers is likely to be ready for the market before the four-point belt, Rouhana says. But both devices offer marked safety gains over existing three-point seat belts, he says.

Ford's testing shows that four-point belts result in a 50 percent cut in chest deflection, the measurement indicating whether a person would be hurt in a crash. Because the buckle assembly sits on the lap and not the side, Ford is working on an adapter for pregnant women to reduce pressure on a fetus during a crash.

Inflatable belts are meant to equal the protection that regular airbags provide to front-seat occupants. A cylindrical tube packaged inside the rear-seat shoulder belts inflates during an accident to spread the forces of a crash over a greater area of the body, reducing chest injuries. The belts also help catch the passenger's chin, reducing neck injuries.

Rouhana says the inflatable belts will help reduce injuries for small children and elderly passengers particularly.