Volvo Car Corporation and its parent Ford Motor Company say they are making progress with their collaborative four-point seat belt project.

The Sweden-based development team is headed by Volvo's senior safety engineer Christer Gustafsson and Ford safety technical specialist David Wagner.

The advantages of a four-point seat belt are that they distribute the crash forces over more of the chest which reduces the pressure on the rib cage, heart and lungs.

They also help hold the occupant in place during crashes that put limitations on today's belt designs.

Two new styles are being evaluated: the 'X4' design and the 'V4' design. Both have the same objective yet with different and unique solutions.

The X4 system uses a standard three-point belt plus a single belt that comes over the shoulder, down across the torso and attaches near the lap belt buckle.

The V4 is a modified design with its design roots in car racing.

The developers say that occupant fitting is as simple as putting on a backpack -'over the shoulder/over the shoulder and click'.

Both designs have shown to be effective in rollover and side impacts during laboratory tests.

One major unknown about four-point belts is how users would accept them.

"During the Detroit International Auto Show we asked show attendees to assess ease of use and comfort for both styles," Wagner said.

"This was perhaps the first use of a motor show to conduct one-on-one safety research. We were very eager to watch people's reactions and discuss their concerns. "Consumers were very excited about the prospects of additional safety benefits from the four-point belt. We're still weighing the advantages of both designs."

He added that a few engineering challenges remain, however, but did not elaborate.

"I believe we'll have something in the next three years that meets the expectations of our engineering teams and, of course, those of our customers," said Gustafsson.

"In the near future, we will be entering into discussions with regulatory agencies around the world including the U.S. National Highway Traffic Safety Administration (NHTSA) to discuss our findings and the regulatory implications of four-point belts."

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