VI.  POST-NPRM TESTING

The agency conducted several research projects since publication of the NPRM in an effort to assess whether the proposed changes would reduce the safety currently afforded by child restraints. NHTSA conducted three test projects, which are fully discussed in sections VIII.a.1, VIII.c.1, and VIII.e.1 of this preamble. The first test project related to the effect the revisions to the test seat assembly might have on the dynamic performance of child restraints. Dummies currently specified in FMVSS No. 213 were tested with child restraints on the revised seat assembly, and the performance of the dummies was compared to that observed in compliance tests. The second test project related to assessing any performance differences that may exist between the Hybrid II and the Hybrid III dummies. The third test project involved evaluating whether child restraints tested with the Hybrid III dummies could meet the proposed scaled HIC, chest injury limits, and Nij measures. Reports relating to these projects have been placed in the docket for this rulemaking.

VII.  SUMMARY OF COMMENTS ON THE NPRM

NHTSA received approximately 35 comments on the May 1, 2002 NPRM for this final rule. Commenters included child restraint manufacturers, motor vehicle manufacturers, motor vehicle dealers and other industry associations, child passenger safety consumer groups, the National Transportation Safety Board, child safety research and testing organizations, and private individuals. The Juvenile Products Manufacturers Association (JPMA) conducted a series of 80 sled tests of child restraints in response to the NPRM and included the results of the testing in its comment.

a.  General Comments on the Proposals

The commenters generally expressed support for the regulatory goals of the NPRM to enhance child passenger safety. [4]   However, many underscored concerns that the rulemaking undertaken by the agency in response to the TREAD Act could possibly indirectly cause a reduction in child passenger safety, particularly with respect to applying new (neck loading, chest deflection) and revised (scaled HIC and chest acceleration limits) injury criteria used to assess the dynamic performance of child restraints. Commenters expressing these concerns were diverse. The JPMA, representing child restraint manufacturers Britax, Cosco, Evenflo, Graco/Century, and Peg Perego, believed that NHTSA should be concerned about "unintended consequences of multiple, unevaluated changes to 213, as well as the adverse consequences of substantial cost increases." In a separate comment on the NPRM, Evenflo expressed opposition to "revisions that do not have proven likelihood of enhancing child passenger safety on an aggregate basis."  Evenflo urged: "Our goal should be to adopt changes that will definitively enhance child passenger safety, not to undertake changes solely for the purpose of making changes." Graco was concerned that some portions of the proposed revisions may have little benefit to child passenger safety and may "negatively affect the past efforts of the agency."  The commenter said it assumed that costs of child restraints will increase "because of increased testing costs and most likely increased parts or the use of more advanced technology that will enable the restraints to meet new requirements."  The commenter was concerned that, as the child restraint costs rise, the rates of child restraint use may fall.

This concern was echoed by other commenters. TraumaLink at the Children's Hospital of Philadelphia stated that data collected through its "Partners for Child Passenger Safety" study indicate that children in child restraints do extremely well in all types of crashes. "The extremely low injury rate in child restraints indicates that despite substantial misuse, these devices perform exceedingly well across the range of crash severities and directions of impact….It is important to consider the unintended consequences of these [proposed] changes, both in terms of inadvertent reduction in the current excellent performance of the CRS [child restraint system] or the resultant increase in cost."  The National Safe Kids Campaign (Safe Kids) urged the agency "to be mindful of the practicalities and costs associated with changes that might overly burden child restraint and vehicle manufacturers, thereby requiring them to discontinue certain product models or pass on unreasonable costs to consumers. Child safety seats must remain both affordable and safe." The American Academy of Pediatrics stated, "While the Academy strongly supports the proposed measures to make child restraints even more protective than they are today, these improvements cannot come at the expense of fewer children using child restraints or more children using outdated car safety seats." The Association of International Automobile Manufacturers, Inc., expressed concern that "the lack of use or the misuse of child restraint systems presents a far greater opportunity to improve child passenger safety than seeking enhanced performance of child restraint systems, particularly if the consequence of the enhanced performance is decreased use and increased misuse." 

Safe Kids also expressed concern that increased prices of child restraints could affect State child restraint use laws. Safe Kids stated that most parents and caregivers will be expected to purchase a minimum of two or three restraints for each child to comply with evolving State child restraint use laws that extend coverage to more and more children. "As those seats become more expensive, legislators may be reluctant to make important legislative improvements to their states child restraint laws." 

b.  Updated Bench Seat

There was unanimous support for amending Standard No. 213's specifications for the test seat assembly used to test child restraints in the agency's compliance tests. Almost all of the commenters believed that the test seat assembly should be more representative of the seats of newer passenger vehicles. Two commenters (Martha Bidez, Public Citizen) had an opposing view. Ms. Bidez believed that the seat assembly should either have features representing seats in the average age vehicle in the U.S. (which the commenter stated is 9 years old) or features that present the most demanding ("worst case") conditions under which child restraints should be tested. Public Citizen suggested that the agency should adjust its testing, or create another test, that will measure the effectiveness of child restraints in older cars.

Amending the seat cushion angle by increasing it from 8 degrees off horizontal to 15 degrees was generally supported, as was amending the seat back angle by increasing it from 15 degrees off vertical to 22 degrees. Several commenters viewed these changes as aligning the bench seat more with the ECE Regulation 44 seat assembly bench and suggested that the agency completely use the ECE Regulation 44 seat dimensions.

Most commenters agreed with the proposals for amending the seat belts on the test seat assembly. Some commenters expressed concerns about certain aspects of the test seat assembly's seat belts that were not addressed by the NPRM, such as the vertical location of the lap belt anchorages.  

On the other hand, commenters did not see eye-to-eye on the proposal to change the seat back to represent a fixed vehicle seat. Supporters of the change believed that a fixed seat back replicates today's seat back in passenger cars and harmonizes with the test bench setups for ECE, Canadian and Australian regulations. Some commenters were concerned that not enough was known about how fixing the seat back would affect child restraint system performance, while others opposed the proposal believing that fixing the seat back would result in a less rigorous test condition.

Several commenters responded to the NPRM's request for comments on the agency's decisions against changing, at this time the length of the bench seat's bottom seat cushion, including a floor to the seat assembly; and changing the stiffness of the seat assembly's cushion. A number of commenters believed that the stiffness of the seat cushion has a strong effect on child restraint performance. Some commenters were uncertain whether performance would be affected and suggested that testing and research be completed before changing the foam.

c.  Crash Pulse

The comments focused generally on the issues of the sled pulse shape (widening of the corridor) and severity. Many commenters agreed with the agency that widening the corridor of the sled pulse from 80 milliseconds (ms) to approximately 90 ms in duration would allow more laboratories to run the compliance test without decreasing the effectiveness of the testing. However, child restraint manufacturers expressed concern that widening the corridor will make the standard more stringent, because child restraint manufacturers will have to design products that can comply at the new extremes of the compliance corridor. These commenters also believed that a wider test corridor will necessarily lead to more lab-to-lab variability during certification and compliance testing, which, the commenters stated, increases the compliance burden on manufacturers.

ARCCA, Inc. believed that the Standard No. 213 pulse is actually less severe than all of the 30 mph barrier test pulses from actual vehicles, and that the standard's pulse severity should be increased. All other commenters did not want to increase the severity of the crash pulse. Many expressed the view that the velocity change should not be raised because the current test is already reflective of the top few percent of crashes. A number of commenters believed that the crash pulse should be reduced in severity because the most frequent crashes involving children in child restraints are those with lower crash pulse severities than the test pulse. Others believed that a relatively severe, "worst case" scenario should be replicated.

d.  New Dummies

Commenters generally supported using the CRABI and Hybrid III 3-year-old dummies in Standard No. 213 compliance tests, in place of the 9-month and Hybrid II 3-year-old dummies now used by the agency. However, a number of commenters expressed concerns that the Hybrid III 6-year-old dummy's neck was too flexible for use in testing child restraints. These commenters suggested that the agency continue its use of the Hybrid II 6-year-old dummy rather than use the Hybrid III dummy in its place. Most commenters objected to using the weighted Hybrid III 6-year-old dummy (weighted to 62 lb) to assess injury reference values in compliance tests of child restraints recommended for use by children weighing over 50 lb. Most believed that the dummy's weighting produced a dummy that was unrepresentative of a 62 lb child. Some were concerned that the weights could interfere with the proper functioning of the dummy's instrumentation. Some of these commenters suggested that the dummy should be used only to assess the structural integrity of child restraints in the standard's dynamic test, and not the capability of the restraint to limit head excursion or forces to the dummy's head, neck or chest areas.

e.  Application of the Standard

Of the commenters addressing application of the standard, a majority supported increasing the weight limit contained in the "child restraint system" definition. Most of these commenters supported increasing the weight limit to 65 lb with a future increase to 80 lb upon introduction of the 10-year-old dummy. A few commenters opposed establishing 65 lb as an intermediate step in favor of amending the standard directly to 80 lb. There were also a few divergent comments on whether the agency should extend the regulation to a maximum weight beyond that of the heaviest dummy used in the standard.

f.  Injury Criteria

The agency received widely divergent comments on the proposal to limit measurement of HIC to 15 milliseconds and to use the injury criteria of Standard No. 208 that were scaled for children. The Alliance, UMTRI and SafetyBeltSafe supported the use of a 15 ms limit on the head injury criterion (HIC) limit as a more realistic way to assess head and brain injury, with the lower HIC values proposed for each dummy. JPMA stated that it was willing to consider supporting a 15 ms limit (HIC 15), if the agency can undertake research to assure that there will not be unintended consequences from countermeasures needed to meet HIC 15. However, JPMA did not support the other proposed new injury criteria, including the scaled HIC values. The commenter stated that the tests of child restraints it conducted with the proposed CRABI and Hybrid III dummies produced injury reference values that exceeded the proposed limits, which the commenter said is a concern given the high level of effectiveness of current child restraints. The commenter suggested that it might be more feasible to use the FMVSS No. 208 criteria in FMVSS No. 213 if the agency were to specify a "more realistic crash pulse for FMVSS No. 213, such as the one contained in the FMVSS No. 208 sled test."  Graco was concerned that some seats that have historically performed well in the real world and in compliance testing would fail the new criteria.

A few commenters supported while others opposed the proposals to adopt a new chest deflection criterion and to adopt the chest acceleration limits that were scaled for children and incorporated into FMVSS No. 208. JPMA, TraumaLink, UMTRI, SafetyBeltSafe and others opposed incorporation of the proposed chest deflection and reduced chest acceleration limits, because these types of injuries do not occur in children in child restraint systems. These commenters and others suggested that the agency collect data on chest deflection to establish a database that could be used to evaluate these measures more in the future.

Virtually all parties commenting on this aspect of the proposal opposed the modified Nij neck criterion (modified from the criterion in FMVSS No. 208 in that the limits on axial force were excluded). JPMA, SafetyBeltSafe, UMTRI, TraumaLink and others did not support adopting the proposed Nij criterion at this time because the relationship between the criterion and real-world injuries "under the type of loading simulated by FMVSS 213" is "not well established" (quoting UMTRI). SafetyBeltSafe believed that neither Nij as proposed nor Nij with a limit on tension should be used as a compliance criterion unless these are proven to be useful predictors of child neck injury. The Insurance Institute for Highway Safety (IIHS) was concerned that studies of real-world crashes indicate that neck injuries due to inertial forces appear to be rare, and, the commenter stated, it is not clear how child restraints could be better designed to lower neck injury measures.