The Ford inflatable seat belt: How it affects car seats and children

Ford is offering inflatable seat belts for the outboard-rear-seat passengers as a new safety equipment option on 2011 Explorers. The option will be available sometime between late April and late May, according to Ford. The technology does just as the name says—in a crash, a tubular airbag “unzips” from the seams of the seat belt across the occupant’s chest.

The inflatable seat belts have two advantages: First, they spread the crash force over a wider area of the body, potentially reducing the risk of injury to the chest. Second, deployment of the bag tightens the belt, reducing forward movement and reducing the potential for head injury.

Though we foresaw the potential advantages for all rear-seat passengers, as child passenger safety technicians and parents we had some serious concerns. Were the airbags hot, once deployed, like front airbags are? Are the belts thicker, and if so, how is that going to affect child-car-seat installation features such as belt lock-offs, which are already sometimes difficult to use? How does the deployment of the bags affect a child in a child seat installed with the belts? How would the deploying belt affect a sleeping or slouching child seated very close to it?

So we asked Ford these questions and we’re happy to report that many of our concerns were alleviated. Knowing more about the system set our minds at ease, and gave us more reason to believe that an inflatable belt does offer the potential for added protection to rear seat passengers both young and old.

Here’s what we learned:

• Ford has done extensive testing with the belts to confirm their potential to reduce crash forces and movement—reducing the potential for injury to the head and chest. The testing included child-sized dummies and small adult cadavers in a variety of positions that may be of concern, including simulated sleeping children, positions when the head is lying on the belts, and conditions where the belts were positioned under the arms.
• The belts inflate across the chest using compressed gas stored in a small canister. Once a small charge breaks the seal of the canister, the gas deploys the airbag. This is a cold gas system. It actually feels cold or cool to the touch, not hot, as a pyrotechnically charged front airbag system would be.
• The bag is designed to stay inflated for about 6 seconds, unlike a front-seat airbag which deflates immediately. As a result, the inflated belt offers the potential to maintain its benefits during longer crash events, such as rollovers.
• The inflatable belt is indeed thicker—two to three times the thickness of a traditional seat belt. As child passenger safety technicians, this was one of our greatest concerns, because we know how difficult some child car seat features like lock-offs can be, even with normal seat belts. The lock-off on most child seats is designed to lock the lap belt from moving so that it holds the seat or infant seat base securely. The key to the Ford inflatable belt system is that it is not a continuous loop like most lap-and-shoulder belts. Instead, there are separate lap and shoulder belts attached to a specially designed latch plate (the piece that pushes into the buckle). The shoulder belt and the lap belt each have their own retractor system. This allows the lap belt to be locked from moving by pulling it out and switching the retractor beneath the cushion into ALR (automatic locking retractor) mode. This is similar to the switch many parents use today to lock the shoulder portion of most vehicle belts when installing child restraints. The big potential advantage here is that the lockable retractor on the lap belt may eliminate the need for the lock-off feature on some seats, making the seats easier to install. It also means that some child seat manufacturers may need to add or modify instructions that would guide parents to use the belts correctly or modify lock-off designs so that seats could be installed without their use. (See Common mistakes when installing child car seats: What to watch for.)

We recognize that use and acceptance of new safety systems often requires a learning curve. We know that some child-seat manufacturers prohibit the use of the inflatable belts with their child seats and that others are considering doing so. We encourage them to conduct their own tests and installations with the system. Our fear is that parents may opt not to purchase the belts based on a belief that they may prevent secure installation of their child seats. This would potentially eliminate a feature that may make kids safer when they are big enough to use the belts alone. We will try many of our own child seats with the Ford inflatable belt as soon as it becomes available for purchase.

—Jennifer Stockburger, program manager, vehicle and child safety