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Saturday, December 31, 2005

Four Point Belt Test Drive

I recently had the opportunity to try out a prototype 4-point seatbelt system intended for street vehicles. I was invited to try the system out on a short test drive, and take a survey afterwards. I won't divulge the company developing the system, I am sure they will come out when they are ready. The system was installed in a Ford Mustang GT, and was intended to be sold to the sports/enthusiast consumer.

The system consists of two shoulder belts, which you slip each arm through, and buckle together centered at your waist. The lower straps form a lap belt, with a slight arch upwards towards the buckle. The lower straps are attached to automatic tensioners, which prevent the buckle from riding up on your belly. This is key, because if the buckle is too high, you could slide under the belt ("submarine") in a severe accident. The upper straps have traditional springy tensioners, which allow you to twist left and right, or lean forward as needed.

The system was a little more work to get into, since you have to thread each arm through a loop, but once buckled in, it was quite comfortable. Having both shoulders covered gave a very secure feeling, and having the buckle centered at the waist made it very easy to find and release the belt. Driving did not require any significant amount of additional effort, even in a manual transmission car. I would buy a 4-point system if it was offered, without hesitation.

The engineer running the survey told me that NHTSA is very interested in 4-point belts, because they spread the deceleration loads more evenly and symmetrically over a person's torso. In order for any car maker to offer 4-point belts, the regulations of FMVSS 208 would have to be amended to allow the design.

A major concern is how consumers would perceive the 4-point belts. Some people would prefer them, because of the added safety and "racecar" image, but some people would be annoyed by the extra work in putting on the belt. Another question is how very large, or pregnant passengers would wear the belts.

Several automakers and suppliers are working on improved seat belt designs. Volvo has been experimenting with 4-point safety belt designs, including a crossover type which forms an X over an occupant's chest. Nissan has revealed a 4-point system in its Sport concept car. Ford recently announced an inflatable seatbelt concept, which would spread forces out over a wider area by inflating an airbag built into a 3-point belt.


Anonymous said...

A friend had a four point system in his Shelby Mustang in the '60s. It was easy and comfortable, with dual inertia straps mounted to the roof or rollbar (can't remember which). Given what we know about crashes these days, it simply amazes me that the industry hasn't upgraded by now. A three point belt is only slightly better than a lap belt; right now the airbag is doing the serious protecting. You'll slide out of a single diagonal shoulder strap in an instant in any kind of serious crash, or else get "sliced" by it.

Anonymous said...

I do not wear a seat belt now because of the way it comes across my neck. I would like to try a 4-point seat to see how this would feel. I think it would be a good idea to have a choice between a 3 and 4 point seat belt

The Auto Prophet said...

Anonymous #2,

You should reconsider. You are asking for trouble by not wearing a seatbelt--you have a real good chance of getting killed in a relatively minor accident. Airbags are designed to protect unbelted passengers at 25mph--if you have a 40mph crash, all bets are off.

You can get a device which repositions the belt straps, or pads them, to avoid discomvfort or poor fit. These are availible for kids and adults.

Don't tempt fate.

Jon said...

Even today 4 point seatbelts are not fitted in new vehicles. It's crazy.

Australia tried to implement legislation a few years back but to no avail.

The Global Herald Motoring

Levi Day said...

This is really cool! I always wanted to have a 4 point seat belt in my cars. Although if you drive with a harness you look like a nutcase...