PROPOSED DUMMIES, INJURY CRITERIA, AND OTHER CHANGES
This chapter discusses the proposed changes for FMVSS 213. These changes include: Hybrid III test dummies, injury criteria and its corresponding injury criterion performance limits (ICPLs), seat assembly, and sled crash pulse. In addition, the chapter provides injury probability risk curves that would be used in the benefit estimates.
A. Proposed Dummies
The agency proposes that FMVSS 213 use a 12monthold CRABI and the more advanced Hybrid III dummies to replace the Hybrid II dummies. The Hybrid III dummies include a 3yearold and a 6yearold dummy. To further protect older children weighing between 50 and 80 pounds, the agency also proposes a 65pound weighted 6yearold dummy. This section discusses the proposed Hybrid III dummies and the weighted 6yearold dummy. Readers can consult the following references for more information on dummy research and analysis:
Hybrid III vs Hybrid II
Currently, FMVSS 213 specifies the 9month, and Hybrid II 3year and 6yearold dummies be used in compliance tests. The 9month old dummy is only used to measure head excursion. The Hybrid II 3 and 6yearold dummies are instrumented to measure HIC and chest acceleration and are used to measure head excursion and knee excursion. The12monthold infant (CRABI) and the Hybrid III 3 and 6yearold child dummies are equipped with greater instrumentation. These dummies contain a more advanced and biofidelic neck design. Readers can consult the NHTSA technical report titled "A Comparative Evaluation of Hybrid II and Hybrid III Child Dummy Families" for a detailed assessment of dummy equivalency research.
Weighted 6YearOld Dummy
The weighted 6yearold dummy is the Hybrid III 6yearold dummy instrumented with an extra weight to 65 pounds. A 1994 NHTSA study ^{(1)} has shown that children do not properly fit into standard vehicle safety belt systems without booster seats until they reach 4 foot nine inch height which correlates an average weight of 80 pounds. To improve the protection of the children weighing between 50 and 80 pounds, the agency is considering a 10yearold dummy. A Hybrid III 10yearold dummy that weighs approximately 78 pounds is under development. The weighted 6yearold dummy is the agency's nearterm solution to cover the weight gap until the completion of the 10yearold dummy. Readers can consult NHTSA's report "Evaluation of the Weighted Hybrid III SixYearOld Dummy, June, 2001" for detailed information.
B. Proposed Injury Criteria
The current FMVSS 213 uses head injury criterion (HIC), chest acceleration (chest g), head excursion, and knee excursion to assess the performance of child restraints. HIC unlimited (HIC_{unlimited}), an unrestricted time interval measurement, is used to predict head injury. The injury criteria performance limits (ICPL) are: 1000 for HIC_{unlimited}, 60 g for chest acceleration, 28 (test child restraint with tether) or 32 (without tether) inches for head excursion, and 36 inches for knee excursion. The ICPLs are the same for all dummy sizes.
The agency is proposing to amend FMVSS 213 to incorporate FMVSS 208 injury criteria except for the neck limits and its ICPLs. FMVSS 208 requires HIC, chest g , chest deflection, and neck criteria (Nij) with peak neck tension and compression limits to minimize the risk from a deploying air bag. The required ICPLs in FMVSS 208 are different depending on the dummy size to ensure a consistent performance requirement and the adequate safety protection to all occupants.
The proposed HIC as in FMVSS 208 is measured at a 15millisecond time window (HIC_{15}), as opposed to an unlimited HIC measurement in the current FMVSS 213. For adult dummies, there was a high correlation between HIC_{36} and HIC_{15 }for long duration pulses. A HIC_{36} 1000 is correlated to HIC15 700. HIC_{15} is more stringent for short duration pulse (< 25 millisecond pulses). The agency is proposing to use a different set of neck axial force and neck moment intercept values from those specified in the FMVSS 208 for the Nij calculation. The Nij intercept values used in the FMVSS 208 are for outofposition child occupants since the outofposition tests were only required for child dummies. However, in the FMVSS 213 test environment, the child dummies are considered to be tested inposition. Therefore, the agency is proposing a set of inposition neck intercept values to be used to calculate Nij. In comments to the FMVSS 208, AMA had recommended inposition Nij intercept values for all dummy size. The agency is proposing FMVSS 213 to adapt these recommended inposition critical values. See Table III1 for these critical neck values. The FMVSS 208 does not require the weighted 6yearold dummy. The injury criteria for the weighted 6yearold dummy were scaled from the 6yearold. Other than the chest deflection ICPL, the HIC_{15}, Chest g's, and Nij ICPLs are proposed to be the same as the 6yearold. Readers please consult the report "Development of Improved Injury Criteria for the Assessment of Child Restraint Systems" for a comprehensive scaling methodology and analysis.
The development of these injury criteria and the corresponding ICPLs curves was documented in NHTSA's report "Supplement: Development of Improved Injury Criteria for the Assessment of Advanced Automotive Restraint Systems  II, March 2000 ^{(2)}." Also, readers please see NHTSA report "Final Economic Assessment, FMVSS No 208, Advanced Air Bags, May 2000" for a summary of the injury criteria and probability curves.
HIC_{15} vs HIC_{unlimited}
NHTSA's Vehicle Research and Test Center (VRTC) has analyzed FMVSS 213 pulse sled test data and the New Car Assessment Program (NCAP) full scale vehicle tests with a 3yearold dummy to compare HIC_{15} to HIC_{unlimited}. Figures III1 and III2 (adapted from report as shown below) indicate that a linear correlation exists between HIC_{36} and HIC_{15}. Figure III1 using the VRTC sled test data shows that HIC_{15} = 0.5911 * HIC_{unlimited}, i.e., HIC_{15 }591 = HIC_{unlimited} 1000. Figure III2 using the NCAP test data shows that HIC_{15} = 0.6113 * HIC_{unlimited}, i.e., HIC_{15 }611 = HIC_{unlimited} 1000. Based on these data, the agency's proposed head injury criteria HIC_{15} with its lower performance limit (570 for 3yo) is slightly more stringent than the current HIC_{unlimited} with a performance limit of 1000. The proposed 390 HIC_{15 }for CRABI based on scaling is equivalent to the 570 HIC_{15 }for the 3yearold dummy. Thus, the proposed HIC_{15} requirement is also more stringent than 1000 HIC_{unlimited. } Readers please see the report "Preliminary Dynamic Evaluation of Proposed 213 Side Impact Test Procedure" for a detailed analysis.
Figure III1
HIC_{15} vs HIC _{unlimited} HIC Using VRTC FMVSS 213 Pulse Sled Test Data
Figure III2
HIC_{15} vs HIC _{unlimited} HIC Using NCAP Test Data
Summary of ICPL Proposal
Head  The agency is proposing HIC_{15} to be used to measure head injury. HIC_{15 }was developed from short duration, hard rigid surface, cadaveric head drop data and was designed to minimize skull fracture/brain injury due to head contacts with interior compartment components. The agency proposes HIC_{15}=390 for the 12monthold CRABI, HIC_{15}=570 for the 3yearold, and HIC_{15}=700 for the 6yearold and the weighted 6yearold dummies. Table III1 summarizes the ICPL requirements for each child dummy size.
Neck  NHTSA is proposing neck injury criterion Nij. This criterion combines neck axial force (F_{Z}  tension/compression) and neck moment (M_{Y } flexion/extension) into one ICPL. Nij represents four combinations of axial force F_{Z} (tension/compression) and neck moment M_{Y} (flexion/extension) to measure four primary types of cervical injuries: tensionextension (N_{TE}), tensionflexion (N_{TF}), compressionextension (N_{CE}), and compressionflexion (N_{CF}). To calculate Nij, each measurement (F_{Z} and M_{Y}) recorded by the upper neck load cell is first normalized against the critical intercept values for each specific dummy. The normalized loads and moments can be expressed as: F_{NZ} = F_{Z} / F_{ZCRIT.}, and M_{NY} =M_{Y} / M_{Y CRIT.}, where F_{Z CRIT. }and M_{Y CRIT.} are the critical intercept values. Table III1 shows the proposed inposition critical values for different child dummies. AMA recommended these critical values. Nij then is the summation of the normalized neck axial force and normalized neck moment at the occipital condyle, i.e., Nij = F_{NZ} + M_{NY}.
NHTSA is proposing that Nij values can not exceed 1.0 at any point in time regardless of the magnitude of axial force and neck moment, i.e., the agency only requires the maximum of (N_{TE}, N_{TF}, N_{CE}, and N_{CF}) can't be greater than 1.0.
NHTSA is not proposing the neck tension and compression limits. Based on NHTSA's recent sled tests and vehicle crash tests with child dummies in child safety seats, most child safety seats failed the additional tension and compression inposition injury limits proposed by AMA for children. However, NASS data and previous published literature indicate that neck injuries in children exposed to FMVSS 213type conditions are rare. This suggests that the inposition tension and compression limits for children proposed by AMA are too conservative. Therefore, FMVSS 213 does not consider the additional neck tension and compression limits.
Chest Acceleration (chest g's)  The proposed ICPLs for chest g's are: 50 g's for the 12monthold CRABI, 55 g's for the 3yearold, and 60 g's for both 6yearold and weighted 6yearold.
Chest Deflection  The proposed ICPLs for chest deflection are: 30 mm (1.2") for the 12monthold CRABI, 34 mm (1.4") for the 3yearold, 40 mm (1.6") for the 6yearold, and 42 mm (1.7") for the weighted 6yearold.
Table III1 summarizes the proposed FMVSS 213 injury criteria and its ICPLs. Note that FMVSS 208 does not require a weighted 6yearold dummy. The ICPLs for the weighted 6yearold dummy are scaled from the injury values of the 6yearold dummy.
Table III1
Proposed FMVSS 213 Injury Criteria and Injury Criteria Performance Limits
Injury Criteria  Hybrid III Child Dummy Size  

12Month Old CRABI 
3YearOld  6YearOld  Weighted 6YearOld*** 

Head Criterion (HIC_{15ms})  390  570  700  700 
Neck Criterion (Nij)  1  1  1  1 
Critical Neck Value*  

1460  2340  3096  3096 

1460  2120  2800  2800 

43  68  93  93 

17  30  42  42 
Thoracic Criteria  

50  55  60  60 

30 1.2" 
34 1.4" 
40 1.6" 
42 1.7" 
Head Excursion **  

720 28" 
720 28" 
720 28" 
720 28" 

813 32" 
813 32" 
813 32" 
813 32" 
Knee Excursion (mm)**  915 36" 
915 36" 
915 36" 
915 36" 
C. Injury Risk Curves
The injury curves are used to estimate the probability of risk of a fatality or injury at a given injury value. The difference between the probabilities of a given set of crash test injury values and of the proposed ICPLs would be used to assess the benefits of the proposed rulemaking. The following figures and formulas show the injury risk curves for head, neck, and thorax injuries. These injury risk curves are adapted from FVMSS 208. Note that the agency believes that the new proposal would impact only on MAIS 2+ injuries, thus, this section provides only MAIS 2+ through 5+ and fatality injury probability risk curves. The development of original injury probability curves was documented in NHTSA's report "Supplement: Development of Improved Injury Criteria for the Assessment of Advanced Automotive Restraint Systems  II, March 2000^{ (3)}." Also, readers please see NHTSA report "Final Economic Assessment, FMVSS NO 208, Advanced Air Bags, May 2000" for a summary of the injury probability curves.
Head Injury Criterion (HIC_{15})
The HIC_{15} probability curves are used to measure the chances that a vehicle occupant would receive certain MAIS head injury at a given HIC value. The analysis uses both variations of Prasad/Metez and Hertz (lognormal)^{ (4)} curves to estimate head injury probabilities. These variations were derived by a shifting process  mapping the probabilities at 700 HIC_{15} to those of 1000 HIC_{36.} The proposed HIC_{15} ICPL is 390 for CRABI, 570 for 3yearold, and 700 for both 6 and weighted 6yearold dummies. The probability risks for these HIC_{15} values are the same and all equate to the 700 HIC_{15} level of a 6yearold (or a weighted 6yearold). Note that the HIC_{15} probability curves are the same for the 6yearold, the weighted 6yearold, and adults because they have the same 700 HIC_{15 }ICPL.
Prasad/Mertz Probability Curves
Tables III2 shows the probability risk values that are derived from the variation of the Prasad/Mertz HIC_{15 }curves for the 6yearold. For children less than 6 years old, the injury probabilities need to be scaled accordingly for children represented by a 3yearold or 12month old CRABI. For example, the probability for CRABI at 390 HIC_{15} is equivalent to that at 570 HIC_{15} for 3yearold and 700 HIC_{15} for 6yearold. The following are the HIC_{15} probability formula (derived from the Prasad/Mertz curves) used to generate 6yearold head probability values in Table III2 and Figure III1. These curves are the same for the weighted 6yearold.
AIS 2+ Percent Injury Probability = [1 / (1 + exp ^{(2.49 +140/HIC  0.00690*HIC )})] X 100%.
AIS 3++ Percent Injury Probability = [1 / (1 + exp ^{(3.39 +140/HIC  0.00531*HIC )})] X 100%.
AIS 4+ Percent Injury Probability = [1 / (1 + exp ^{(4.90 +140/HIC  0.00501*HIC )})] X 100%.
AIS 5+ Percent Injury Probability = [1 / (1 + exp ^{(7.82 +140/HIC  0.00613*HIC )})] X 100%.
Fatality Percent Injury Probability = [1 / (1 + exp ^{(12.14 +140/HIC  0.00807*HIC )})] X 100%.
Table III2
Prasad/Mertz HIC_{15} Probability Risk Values* for 6YearOld Dummy
HIC15  MAIS 1  MAIS 2  MAIS 3  MAIS 4  MAIS 5  Fatal  No Injury 

50  1.3%  0.4%  0.2%  0.1%  0.0%  0.0%  98.0% 
100  7.9%  2.5%  1.1%  0.3%  0.0%  0.0%  88.2% 
150  16.9%  5.6%  2.2%  0.6%  0.0%  0.0%  74.6% 
200  26.5%  9.4%  3.6%  0.9%  0.1%  0.0%  59.4% 
250  34.5%  14.2%  5.3%  1.4%  0.1%  0.0%  44.5% 
300  39.4%  19.8%  7.4%  1.9%  0.2%  0.0%  31.4% 
350  40.4%  25.7%  9.9%  2.6%  0.2%  0.0%  21.2% 
400  38.1%  31.4%  12.8%  3.4%  0.3%  0.0%  13.9% 
450  33.6%  36.3%  16.3%  4.5%  0.4%  0.0%  8.9% 
500  28.0%  39.8%  20.2%  5.8%  0.6%  0.0%  5.6% 
550  22.4%  41.4%  24.3%  7.4%  0.9%  0.0%  3.5% 
600  17.3%  41.2%  28.6%  9.4%  1.2%  0.0%  2.2% 
650  13.1%  39.4%  32.7%  11.8%  1.6%  0.1%  1.4% 
700  9.7%  36.3%  36.3%  14.6%  2.2%  0.1%  0.8% 
750  7.1%  32.4%  39.1%  17.7%  3.0%  0.2%  0.5% 
800  5.1%  28.1%  40.8%  21.2%  4.1%  0.3%  0.3% 
850  3.7%  23.8%  41.4%  25.0%  5.5%  0.4%  0.2% 
900  2.6%  19.8%  40.8%  28.8%  7.3%  0.6%  0.1% 
950  1.9%  16.2%  39.0%  32.4%  9.6%  0.9%  0.1% 
1000  1.3%  13.1%  36.3%  35.4%  12.5%  1.3%  0.0% 
1050  0.9%  10.4%  33.0%  37.7%  16.0%  2.0%  0.0% 
1100  0.7%  8.2%  29.2%  38.8%  20.1%  3.0%  0.0% 
1150  0.5%  6.5%  25.4%  38.6%  24.7%  4.4%  0.0% 
1200  0.3%  5.0%  21.6%  37.1%  29.4%  6.5%  0.0% 
1250  0.2%  3.9%  18.1%  34.4%  33.9%  9.4%  0.0% 
1300  0.2%  3.0%  15.0%  30.8%  37.5%  13.5%  0.0% 
1350  0.1%  2.4%  12.2%  26.6%  39.7%  19.0%  0.0% 
1400  0.1%  1.8%  9.9%  22.3%  39.9%  26.1%  0.0% 
1450  0.1%  1.4%  7.9%  18.1%  37.9%  34.6%  0.0% 
1500  0.0%  1.1%  6.3%  14.3%  34.0%  44.3%  0.0% 
1550  0.0%  0.8%  5.0%  11.1%  28.6%  54.4%  0.0% 
1600  0.0%  0.6%  4.0%  8.4%  22.8%  64.2%  0.0% 
1650  0.0%  0.5%  3.1%  6.3%  17.2%  72.9%  0.0% 
1700  0.0%  0.4%  2.4%  4.6%  12.4%  80.2%  0.0% 
1750  0.0%  0.3%  1.9%  3.4%  8.6%  85.8%  0.0% 
1800  0.0%  0.2%  1.5%  2.4%  5.7%  90.1%  0.0% 
1850  0.0%  0.2%  1.2%  1.7%  3.7%  93.2%  0.0% 
1900  0.0%  0.1%  0.9%  1.2%  2.4%  95.3%  0.0% 
1950  0.0%  0.1%  0.7%  0.9%  1.5%  96.8%  0.0% 
2000  0.0%  0.1%  0.6%  0.6%  0.9%  97.9%  0.0% 
Figure III1
Head Injury Probability vs HIC_{5} for 6YearOld Dummy
(Derived From Prasad/Mertz Curves)
The HIC_{15} injury probability curves for children represented by the 3yearold dummy are:
AIS 2+ Percent Injury Probability  = [1 / (1 + exp ^{(2.49 + 114/HIC  0.00847*HIC)})] X 100% 
AIS 3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.39 + 114/HIC  0.00653*HIC)})] X 100% 
AIS 4+ Percent Injury Probability  = [1 / (1 + exp ^{(4.90 + 114/HIC  0.00616*HIC)})] X 100% 
AIS 5+ Percent Injury Probability  = [1 / (1 + exp ^{(7.82 + 114/HIC  0.00753*HIC)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1 + ^{exp (12.24 + 114/HIC  0.00991*HIC)})] X 100% 
The HIC_{15} injury probability curves for children represented by the 12monthold CRABI are:
AIS2+ Percent Injury Probability  = [1 / (1 + exp ^{(2.49+78/HIC  0.01238*HIC)})] X 100% 
AIS3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.39+78/HIC  0.00954*HIC)})] X 100% 
AIS4+ Percent Injury Probability  = [1 / (1 + exp ^{(4.90+78/HIC  0.00900*HIC)})] X 100% 
AIS5+ Percent Injury Probability  = [1 / (1 + exp ^{(7.82+78/HIC  0.011000*HIC)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1 + exp ^{(12.24+78/HIC  0.01449*HIC)})] X 100% 
Lognormal Probability Curves
Table III3 and Figure III2 shows the probability risk values derived from the lognormal curves for children represented by the 6yearold dummy. These curves are the same as those of weighted 6yearold and adults. Similarly, the variation of the lognormal curves for children represented by the 3yearold and 12monthold CRABI dummies can be derived using the same shifting process. These probability values are shown in Table III4 and Table III5, respectively.
Figure III2
Head Injury Probability vs HIC_{15} for 6YearOld Dummy
(Derived From Lognormal Curves)
Based on Table III2, the variation of Prasad/Mertz curves, at the HIC_{15} ICPL level, a 6yearold child occupant in the frontal crash would have a 89.4 percent chance to receive a MAIS 25 nonfatal head injury (at 700 HIC_{15}, add together 36.3% for MAIS 2, 36.3% for MAIS 3, 14.6% for MAIS 4, and 2.2% for MAIS 5) and have about 0.1 percent chance to receive a fatal head injury.
Based on Table III3, the variation of the lognormal curves, at the ICPL level, a 6yearold child would have a 40.53 percent chance to receive a MAIS 25 nonfatal head injury (at 700 HIC_{15}, add together 24.48% for MAIS 2, 12.21% for MAIS 3, 1.91% for MAIS 4, and 2.13% for MAIS 5), and have about 6.84 percent chance to receive a fatal head injury.
Neck Injury Criteria (Nij)
The formulas for Percent Injury Probability at AIS 2+ through AIS 5+ injury, as a function of Nij values are as follows:
AIS 2+ Percent Injury Probability = [1/ (1 + exp ^{(2.0536 1.1955*Nij )})] X 100%.
AIS 3+ Percent Injury Probability = [1/ (1 + exp ^{(3.227  1.969*Nij )})] X 100%.
AIS 4+ Percent Injury Probability = [1/ (1 + exp ^{(2.693 1.196*Nij )})] X 100%.
AIS 5+ Percent Injury Probability = [1/ (1 + exp ^{(3.817  1.196*Nij )})] X 100%.
Fatality Percent Injury Probability = [1/ (1 + exp ^{(3.817  1.196*Nij )})] X 100%. (Same as AIS 5+)
Table III3
Lognormal HIC_{15} Probability Risk Values* for 6YearOld Dummy
HIC15  MAIS 1  MAIS 2  MAIS 3  MAIS 4  MAIS 5  Fatal  No Injury 

50  13.99%  0.07%  0.00%  0.00%  0.00%  0.00%  85.94% 
100  33.88%  0.86%  0.04%  0.00%  0.00%  0.00%  65.22% 
150  47.45%  2.73%  0.23%  0.01%  0.00%  0.00%  49.58% 
200  55.51%  5.35%  0.71%  0.02%  0.02%  0.01%  38.38% 
250  59.73%  8.33%  1.50%  0.07%  0.06%  0.04%  30.27% 
300  61.40%  11.31%  2.57%  0.16%  0.14%  0.13%  24.29% 
350  61.41%  14.10%  3.84%  0.30%  0.27%  0.31%  19.77% 
400  60.33%  16.59%  5.22%  0.47%  0.46%  0.63%  16.30% 
450  58.57%  18.71%  6.64%  0.68%  0.69%  1.12%  13.59% 
500  56.39%  20.47%  8.00%  0.92%  0.96%  1.81%  11.45% 
550  53.99%  21.87%  9.27%  1.17%  1.25%  2.73%  9.72% 
600  51.47%  22.96%  10.40%  1.42%  1.56%  3.87%  8.32% 
650  48.93%  23.74%  11.39%  1.67%  1.85%  5.25%  7.17% 
700  46.41%  24.28%  12.21%  1.91%  2.13%  6.84%  6.22% 
750  43.95%  24.60%  12.87%  2.12%  2.39%  8.64%  5.43% 
800  41.59%  24.72%  13.38%  2.31%  2.62%  10.62%  4.76% 
850  39.32%  24.70%  13.73%  2.48%  2.81%  12.77%  4.19% 
900  37.16%  24.54%  13.95%  2.62%  2.97%  15.05%  3.71% 
950  35.11%  24.26%  14.06%  2.73%  3.10%  17.44%  3.30% 
1000  33.18%  23.90%  14.05%  2.82%  3.18%  19.93%  2.94% 
1050  31.36%  23.46%  13.95%  2.89%  3.24%  22.47%  2.63% 
1100  29.64%  22.98%  13.75%  2.94%  3.26%  25.07%  2.36% 
1150  28.01%  22.45%  13.51%  2.95%  3.26%  27.69%  2.13% 
1200  26.50%  21.88%  13.19%  2.96%  3.24%  30.31%  1.92% 
1250  25.07%  21.29%  12.84%  2.95%  3.18%  32.93%  1.74% 
1300  23.72%  20.69%  12.44%  2.93%  3.11%  35.53%  1.58% 
1350  22.46%  20.07%  12.02%  2.89%  3.02%  38.10%  1.44% 
1400  21.28%  19.45%  11.58%  2.83%  2.93%  40.62%  1.31% 
1450  20.16%  18.84%  11.12%  2.77%  2.82%  43.09%  1.20% 
1500  19.11%  18.23%  10.65%  2.71%  2.69%  45.51%  1.10% 
1550  18.13%  17.61%  10.19%  2.63%  2.57%  47.86%  1.01% 
1600  17.21%  17.01%  9.71%  2.56%  2.44%  50.14%  0.93% 
1650  16.34%  16.43%  9.24%  2.48%  2.30%  52.36%  0.85% 
1700  15.52%  15.85%  8.78%  2.39%  2.17%  54.50%  0.79% 
1750  14.75%  15.29%  8.32%  2.31%  2.04%  56.56%  0.73% 
1800  14.03%  14.75%  7.87%  2.22%  1.91%  58.55%  0.67% 
1850  13.35%  14.21%  7.45%  2.13%  1.77%  60.47%  0.62% 
1900  12.70%  13.70%  7.02%  2.04%  1.65%  62.31%  0.58% 
1950  12.10%  13.19%  6.62%  1.95%  1.52%  64.08%  0.54% 
2000  11.53%  12.71%  6.22%  1.87%  1.40%  65.77%  0.50% 
Table III4
Lognormal HIC_{15} Probability Risk Values for 3YearOld Dummy
HIC15  MAIS 1  MAIS 2  MAIS 3  MAIS 4  MAIS 5  Fatal  No Injury 

50  18.94%  0.16%  0.00%  0.00%  0.00%  0.00%  80.90% 
100  40.86%  1.60%  0.10%  0.00%  0.00%  0.00%  57.44% 
150  53.44%  4.48%  0.52%  0.01%  0.02%  0.00%  41.53% 
200  59.48%  8.06%  1.42%  0.06%  0.05%  0.04%  30.89% 
250  61.49%  11.72%  2.74%  0.18%  0.15%  0.15%  23.57% 
300  61.11%  15.06%  4.34%  0.36%  0.33%  0.41%  18.39% 
350  59.34%  17.90%  6.07%  0.59%  0.59%  0.90%  14.61% 
400  56.80%  20.18%  7.77%  0.87%  0.92%  1.67%  11.79% 
450  53.86%  21.94%  9.33%  1.18%  1.27%  2.78%  9.64% 
500  50.75%  23.21%  10.69%  1.49%  1.65%  4.23%  7.98% 
550  47.64%  24.04%  11.83%  1.79%  2.00%  6.03%  6.67% 
600  44.60%  24.53%  12.72%  2.06%  2.32%  8.15%  5.62% 
650  41.67%  24.72%  13.37%  2.30%  2.61%  10.55%  4.78% 
700  38.90%  24.67%  13.79%  2.51%  2.84%  13.20%  4.09% 
750  36.29%  24.43%  14.01%  2.67%  3.03%  16.04%  3.53% 
800  33.85%  24.03%  14.06%  2.80%  3.15%  19.05%  3.06% 
850  31.57%  23.53%  13.95%  2.89%  3.23%  22.16%  2.67% 
900  29.46%  22.92%  13.73%  2.94%  3.27%  25.34%  2.34% 
950  27.51%  22.26%  13.40%  2.96%  3.26%  28.56%  2.05% 
1000  25.68%  21.55%  13.00%  2.96%  3.20%  31.79%  1.82% 
1050  24.00%  20.82%  12.53%  2.93%  3.12%  34.99%  1.61% 
1100  22.44%  20.07%  12.01%  2.88%  3.03%  38.14%  1.43% 
1150  21.00%  19.30%  11.47%  2.82%  2.90%  41.23%  1.28% 
1200  19.66%  18.54%  10.90%  2.75%  2.75%  44.25%  1.15% 
1250  18.42%  17.80%  10.32%  2.66%  2.60%  47.17%  1.03% 
1300  17.27%  17.06%  9.74%  2.57%  2.44%  49.99%  0.93% 
1350  16.21%  16.34%  9.16%  2.46%  2.29%  52.70%  0.84% 
1400  15.22%  15.64%  8.60%  2.36%  2.12%  55.30%  0.76% 
1450  14.31%  14.95%  8.05%  2.25%  1.95%  57.80%  0.69% 
1500  13.45%  14.30%  7.51%  2.14%  1.80%  60.17%  0.63% 
1550  12.67%  13.66%  6.99%  2.04%  1.63%  62.44%  0.57% 
1600  11.93%  13.05%  6.50%  1.93%  1.48%  64.59%  0.52% 
1650  11.24%  12.46%  6.03%  1.82%  1.34%  66.63%  0.48% 
1700  10.60%  11.90%  5.57%  1.72%  1.20%  68.57%  0.44% 
1750  10.00%  11.36%  5.14%  1.63%  1.06%  70.40%  0.41% 
1800  9.45%  10.85%  4.73%  1.53%  0.94%  72.13%  0.37% 
1850  8.93%  10.36%  4.35%  1.43%  0.82%  73.77%  0.34% 
1900  8.44%  9.88%  3.99%  1.35%  0.71%  75.31%  0.32% 
1950  7.99%  9.44%  3.65%  1.26%  0.60%  76.77%  0.29% 
2000  7.56%  9.01%  3.33%  1.18%  0.51%  78.14%  0.27% 
Table III5
Lognormal HIC_{15} Probability Risk Values for 12MonthOld CRABI
HIC15  MAIS 1  MAIS 2  MAIS 3  MAIS 4  MAIS 5  Fatal  No Injury 

50  30.27%  0.62%  0.02%  0.00%  0.00%  0.00%  69.09% 
100  52.75%  4.22%  0.47%  0.02%  0.01%  0.00%  42.53% 
150  60.62%  9.49%  1.88%  0.10%  0.08%  0.07%  27.76% 
200  61.28%  14.57%  4.09%  0.32%  0.31%  0.35%  19.08% 
250  58.63%  18.66%  6.60%  0.67%  0.69%  1.10%  13.65% 
300  54.56%  21.57%  8.99%  1.11%  1.19%  2.49%  10.09% 
350  50.03%  23.44%  10.98%  1.56%  1.72%  4.62%  7.65% 
400  45.52%  24.42%  12.47%  1.98%  2.23%  7.46%  5.92% 
450  41.24%  24.73%  13.44%  2.34%  2.65%  10.94%  4.66% 
500  37.27%  24.55%  13.95%  2.61%  2.96%  14.93%  3.73% 
550  33.66%  24.00%  14.06%  2.80%  3.17%  19.28%  3.03% 
600  30.42%  23.21%  13.85%  2.92%  3.25%  23.87%  2.48% 
650  27.51%  22.26%  13.40%  2.96%  3.26%  28.56%  2.05% 
700  24.89%  21.21%  12.79%  2.95%  3.17%  33.27%  1.72% 
750  22.55%  20.12%  12.06%  2.89%  3.03%  37.90%  1.45% 
800  20.47%  19.01%  11.25%  2.79%  2.85%  42.40%  1.23% 
850  18.61%  17.90%  10.42%  2.67%  2.63%  46.72%  1.05% 
900  16.94%  16.83%  9.57%  2.53%  2.40%  50.83%  0.90% 
950  15.44%  15.80%  8.73%  2.38%  2.16%  54.71%  0.78% 
1000  14.10%  14.80%  7.92%  2.23%  1.92%  58.35%  0.68% 
1050  12.90%  13.85%  7.16%  2.06%  1.69%  61.75%  0.59% 
1100  11.81%  12.96%  6.43%  1.91%  1.46%  64.91%  0.52% 
1150  10.84%  12.11%  5.74%  1.76%  1.25%  67.84%  0.46% 
1200  9.96%  11.32%  5.11%  1.62%  1.05%  70.54%  0.40% 
1250  9.16%  10.58%  4.53%  1.47%  0.88%  73.02%  0.36% 
1300  8.44%  9.88%  3.99%  1.35%  0.71%  75.31%  0.32% 
1350  7.79%  9.24%  3.50%  1.22%  0.56%  77.41%  0.28% 
1400  7.20%  8.63%  3.05%  1.11%  0.43%  79.33%  0.25% 
1450  6.65%  8.07%  2.64%  1.01%  0.31%  81.09%  0.23% 
1500  6.17%  7.54%  2.28%  0.90%  0.21%  82.70%  0.20% 
1550  5.72%  7.05%  1.95%  0.81%  0.12%  84.17%  0.18% 
1600  5.30%  6.60%  1.65%  0.73%  0.03%  85.52%  0.17% 
1650  4.93%  6.17%  1.38%  0.66%  0.00%  86.74%  0.15% 
1700  4.58%  5.78%  1.14%  0.59%  0.00%  87.86%  0.14% 
1750  4.27%  5.41%  0.93%  0.53%  0.00%  88.89%  0.12% 
1800  3.98%  5.07%  0.74%  0.47%  0.00%  89.82%  0.11% 
1850  3.72%  4.75%  0.57%  0.41%  0.00%  90.67%  0.10% 
1900  3.46%  4.46%  0.42%  0.36%  0.00%  91.45%  0.10% 
1950  3.24%  4.18%  0.28%  0.33%  0.00%  92.16%  0.09% 
2000  3.03%  3.92%  0.17%  0.29%  0.00%  92.81%  0.08% 
The Nij values are the normalized numbers adjusted to maintain consistency with respect to the neck injury outcome, thus the Nij probability curves are the same regardless of dummy size. Figure III3 depicts the neck injury probability vs Nij. Note that the fatality probability curve is the same as the AIS 5+ curve.
Figure III3
Neck Injury Probability vs Nij
Thorax Injury Criteria
Chest acceleration limits and chest deflection limits are proposed for each child dummy size.
Chest Acceleration
Injury probability as a function of chest acceleration (chest g's) based on a 3 ms clip of the spinal acceleration on a 6yearold dummy is listed below. The mathematical formulas for the chest g's injury probability curves are the same for the 6yearold, weighted 6yearold, and the adults (same as the 50^{th} percentile male curves ^{(5)} for FMVSS 208) because the ICPL for these dummies are the same at 60 g's.
The chest acceleration injury probability curves for children represented by the 6yearold and weighted 6yearold dummies are:
AIS 2+ Percent Injury Probability = [1 / (1 + exp ^{( 1.2324  0.05760* g)} )] X 100%.
AIS 3+ Percent Injury Probability = [1 / (1 + exp ^{(3.1493  0.06300*} ^{g )} )] X 100%.
AIS 4+ Percent Injury Probability = [1 / (1 + exp ^{(4.3425  0.06300* g )} )] X 100%.
AIS 5+ Percent Injury Probability = [1 / (1 + exp ^{(8.7652  0.06590* g )} )] X 100%
Fatality Percent Injury Probability = [1 / (1 + exp ^{(8.7652  0.06590* g )} )] X 100% (same as AIS 5+ Injury Curve).
Where, g = chest g's.
Figure III4 depicts the chest injury probability vs chest g's. Note that the fatality probability curve is same as the AIS 5+ curve.
Figure III4
Chest Injury Probability vs Chest Acceleration (g's) for 6YearOld Dummy
The chest acceleration injury probability curves for children represented by the 3yearold dummy are:
AIS 2+ Percent Injury Probability  = [1 / (1 + exp ^{(1.2324  0.06284*g)})] X 100% 
AIS 3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.1493  0.06873*g)})] X 100% 
AIS 4+ Percent Injury Probability  = [1 / (1 + exp ^{(4.3425  0.06873*g)})] X 100% 
AIS 5+ Percent Injury Probability  = [1 / (1 + exp ^{(8.7652  0.07189*g)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1 + exp ^{(8.7652  0.07189*g)})] X 100% 
The chest acceleration injury probability curves for children represented by the 12monthold CRABI are:
AIS 2+ Percent Injury Probability  = [1 / (1 + exp ^{(1.2324  0.06912*g)})] X 100% 
AIS 3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.1493  0.07560*g)})] X 100% 
AIS 4+ Percent Injury Probability  = [1 / (1 + exp ^{(4.3425  0.07560*g)})] X 100% 
AIS 5+ Percent Injury Probability  = [1 / (1 + exp ^{(8.7652  0.07908*g)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1+ exp ^{(8.7652  0.07908*g)})] X 100% 
Chest Deflection
The chest deflection injury curves for children represented by the weighted 6yearold, 6yearold, 3yearold, and 12monthold CRABI are derived from the 50^{th} percent male curves^{ (6)} by a shifting process. For example, the curves for the 6yearold dummy were derived by mapping the probability of chest injury at 40 mm (1.6") for the 6yearold dummy to that at 63 mm (2.5") for 50^{th} percentile male dummy. See FMVSS 208 for the original formula for the chest deflection injury probability curves for 50^{th} percentile males. The followings are the chest deflection injury curves for children represented by the 6year old dummy:
AIS 2+ Percent Injury Probability = [1 / (1 + exp ^{(1.8706  0.06991* d) })] X 100%^{ }
AIS 3+ Percent Injury Probability = [1 / (1 + exp ^{(3.7124  0.07481* d ) })] X 100%
AIS 4+ Percent Injury Probability = [1 / (1 + exp ^{(5.0952 0.07481* d ) })] X 100%
AIS 5+ Percent Injury Probability = [1 / (1 + exp ^{(8.8274  0.07229* d ) })] X 100%
Fatality Percent Injury Probability = [1 / (1 + exp ^{(8.8274  0.07229* d ) })] X 100% (same as MAIS 5+ Injury Curve).
Where, d = chest deflection.
Figure III5 depicts the chest injury probability vs chest deflection (mm) for children represented by the 6yearold dummy.
Figure III5
Chest Injury Probability vs Chest Deflection for 6YearOld Dummy
The chest deflection injury probability curves for children represented by the 3yearold dummy are:
AIS 2+ Percent Injury Probability  = [1 / (1 + exp ^{(1.87060.08225*d)})] X 100% 
AIS 3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.71240.08802*d)})] X 100% 
AIS 4+ Percent Injury Probability  = [1 / (1 + exp ^{(5.09520.08802*d)})] X 100% 
AIS 5+ Percent Injury Probability  = [1 / (1 + exp ^{(8.82740.08505*d)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1 + exp ^{(8.82740.08505*d)})] X 100% 
The chest deflection injury probability curves for children represented by the 12monthold CRABI are:
AIS 2+ Percent Injury Probability  = [1 / (1 + exp ^{(1.87060.09322*d)})] X 100% 
AIS 3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.71240.09975*d)})] X 100% 
AIS 4+ Percent Injury Probability  = [1 / (1 + exp ^{(5.09520.09975*d)})] X 100% 
AIS 5+ Percent Injury Probability  = [1 / (1 + exp ^{(8.82740.09639*d)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1 + exp ^{(8.82740.09639*d)})] X 100% 
The chest deflection injury probability curves for children represented by the weighted 6yearold dummy are:
AIS 2+ Percent Injury Probability  = [1 / (1 + exp ^{(1.8706  0.06659*d)})] X 100% 
AIS 3+ Percent Injury Probability  = [1 / (1 + exp ^{(3.7124  0.07125*d)})] X 100% 
AIS 4+ Percent Injury Probability  = [1 / (1 + exp ^{(5.0952  0.07125*d)})] X 100% 
AIS 5+ Percent Injury Probability  = [1 / (1 + exp ^{(8.8274  0.06885*d)})] X 100% 
Fatality Percent Injury Probability  = [1 / (1 + exp ^{(8.8274  0.06885*d)})] X 100% 
In the FMVSS 208, the agency developed a Combined Thoracic Index (CTI), a criterion that combines chest g's and chest deflection, to predict chest injuries. CTI was not required in FMVSS 208. But, for simplifying the complexity of the injury requirements, the Final Economic Assessment for FMVSS 208, Advanced Air bags used the CTI injury curves to estimate the probability of chest injuries. The proposed amendment of FMVSS 213 requires Nij, however, it does not require neck limits as in FMVSS 208, and thus significantly reduce the complexity of the injury criterion requirements. In addition, the chest injury probabilities predicted by CTI curves are comparable to the maximum of the probabilities predicted by chest g's and chest deflection curves. Therefore, this analysis does not use CTI injury curves, instead uses the maximum of injury probabilities predicted by the either the chest g's or chest deflection curves.
D. Proposed Seat Assembly
The agency proposes that the compliance uses a bench seat that represents the production of child safety seats in the today's market. See the accompanying NPRM for a detail discussion.
E. Proposed Crash Pulse
The agency proposes to extend the acceleration from 80 to 90 milliseconds. The extended corridor would not reduce the stringency of the test because the new pulse basically has the same onset rise rate and peak g pressure as the current one. The proposed change would only make it easier to conduct the compliance tests closer to 30 mph.
^{2} Docket Number NHTSA200070133.
^{3} Docket Number NHTSA200070133.
^{4} See the Final Economic Assessment, FMVSS NO. 208, Advanced Air Bags,
Office of Regulatory Analysis & Evaluation, Plans and Polocy, May 2000.
^{5} The original chest acceleration probability formula were listed in
the "Final; Economic Assessment, FMVSS NO 208, Advanced Air Bags, May 2000".
^{6} The original chest acceleration probability formula were listed in
the "Final; Economic Assessment, FMVSS NO 208, Advanced Air Bags, May 2000".