Second, in March of 1992, NHTSA denied a petition seeking a ban or recall of safety belt tension adjusters because there is no evidence correlating the use of seat belt tension adjusters and an increased risk of passenger injuries. The product which was the subject of the petition was a device that clips onto the belt and limits the amount of tension in the belt by preventing complete retraction (similar to the Auto Comfort product discussed in Section V.B). The petition noted that such devices have been banned in Australia for many years. As a result of the petition, NHTSA studied the issue and found that "a 19-city survey of safety belt use consistently showed that 2 percent or less of people wearing safety belts had excessive slack in their shoulder belts." Further, NHTSA considered a separate study conducted by the National Transportation Safety Board (NTSB) of data from actual motor vehicle crash investigations. NHTSA also reviewed their computerized consumer complaint logs and found that no reports alleging that add-on seat belt adjusters caused or exacerbated injuries suffered in a motor vehicle crash.
Based on these investigations, NHTSA found that "no evidence exists to show these devices are being misused to create excess belt slack nor is there proof that using the devices cause real-world problems." Conversely, NHTSA said that "these devices have been used extensively for the last 16 years and based on the 'in-use' data, do not pose an increased safety risk." (as stated in PSLR Vol 20, No. 14, p. 387)
Findings:
NHTSA recognizes the potential benefits of a device which can increase seat belt use by providing increased comfort to users through additional belt adjustments.
NHTSA investigations have found no data to support the claim that Seat belt Adjuster type devices are being misused to create excess slack or that these typesof devices cause real-world problems.