Seat Belt Issue – Known as Energy Management Loop
In an effort to keep our visitors updated on recent developments in product liability cases, our Law Firm herein alerts you to a seatbelt defect called the “energy management loop,” also referred to as “rip stitching.” The loop consists of a portion of the seatbelt that is folded over on itself and sewn together. Unfortunately, the stitching can rip during a car collision, adding several inches of slack to the seatbelt.
The so-called “energy management loop” was designed in an attempt to manipulate crash test results by inducing submarining and therefore reducing head injury numbers in frontal crashes. Rather than making vehicles safer, however, EM loops greatly increase the risk of injury in a collision. There is a wide array of published reports about the hazards associated with seatbelt slack, including slack caused by EM loops. For example, in a report on improper belt use, the Insurance Institute for Highway Safety noted that belt slack, “can diminish or eliminate the effectiveness [of belts] or even induce serious injuries.” Volkswagen, Mercedes, and Toyota have warned about the hazards of seatbelt slack. Mercedes and Toyota have each described in detail how seatbelt retractors could be designed to provide comfortable belt fit without the hazards of slack. A 1988 National Transportation Safety Board report consisting of a case study of 167 automobile crashes found that when slack was present in the belt system, “the opportunity for a degraded level of occupant protection exists.” Given the reduced performance of seatbelts when slack is introduced and the dangers of slack, it is no surprise that most owner’s manuals instruct drivers to pull up on the shoulder portion of the belt to ensure that there is no extra slack in the lap belt.
General Motors has issued several recalls related to EM loops. For example, in 2002, General Motors issued Recall03V117, stating that the EM loop in the driver’s seatbelt buckle assembly introduced as much as 10 inches of slack into the belt in a crash, which could result in partial or complete ejection of a belted driver in a rollover. The recall covered the 1997 Chevrolet Blazer, GMC Jimmy, and Oldsmobile Bravada. To correct this condition the seatbelt assemblies were replaced with a design that did not contain an EM loop. According to GM, the recall was initiated based on claims in which belted occupants were ejected in rollovers.
In 1979, NHTSA proposed an outright ban on seatbelt slack-inducing devices such as window shade devices. Two years later, NHTSA issued a rule to “urge manufacturers to voluntarily limit the amount of slack that can be introduced in their manual belt systems.” In November of 1987, NHTSA issued another ruling, this time subjecting manual seatbelts to dynamic testing, and again expressing concern about seatbelt tension-relieving devices and their potential for increased occupant injury.
Given the dangers of seatbelt slack, it is no surprise that automotive manufacturers provide safety components that have the sole purpose of reducing of reducing seatbelt slack – just the opposite of what the EM loop does. For example, seatbelt pretensioners retract and preload the seatbelt during the first few milliseconds of a crash to compensate for any slack or spool-out. A number of automotive manufacturers feature weblocks, which are webbing clamps that eliminate any spool-out of the webbing stored on the retractor spindle, either by clamping at the retractor or at the D-ring. The purpose of these devices is to reduce as much as possible seatbelt slack in a collisional rollover, because automotive manufacturers are in agreement that seatbelt slack reduces performance of seatbelts and subjects the wearer to partial or complete ejection.
As a result of these studies and reports, many manufacturers have removed seatbelt systems with energy management loops from current models; however, many cars on the road today still have these systems, and many manufacturers have vehicles on the road that contain both EM loops and pretensioners that actually work against each other in a collision.