CHAPTER II. SAFETY PROBLEM




This section estimates the number of child passenger vehicle fatalities and injuries in frontal crashes that could benefit from adapting FMVSS 208 injury criteria. A child is defined as between ages 0 to 12 years old. All the statistics presented here are for children 0 to 12 years old to demonstrate the child injury safety problem ⁽¹⁾. However, only children sitting in child restraints are assumed to be impacted by FVMSS 213 and are used in the benefit estimation.

The real-world crash data used to derive the fatalities and non-fatal injuries in frontal crashes are from the following files: the 1999 Fatality Analysis Reporting System (FARS), the 1999 General Estimates System (GES) ⁽²⁾, and the 1993-2000 Crashworthiness Data System (CDS). Both GES and CDS are sampling systems. CDS has a much smaller sample than does GES, but with a more in-depth investigation of injury profiles. Thus, the multiple years of CDS were used in the detail descriptive statistics analysis to reduce variability.

The fatal frontal crashes in FARS were defined as the initial (IMPACT1) or principal (IMPACT2) impact points in the 11, 12, and 1 o'clock directions. Because data elements describing crash characteristics varied between FARS and CDS, frontal crashes were defined differently in CDS. The frontal crashes in CDS were defined by their principal direction of force (DOF1), the general area of damage (GAD1), and the primary specific horizontal location (SHL1). They included crashes with (1) DOF1 between 11 and 1 o'clock direction, or (2) DOF1 was 10 or 2 o'clock direction and GAD1 was front or side with damage forward of the A-pillar.

The overall fatal problem size was derived from 1999 FARS level. The non-fatal injuries in frontal crashes were derived from 1993-2000 CDS. CDS contains data on all passenger vehicle crashes where at least one passenger vehicle was towed, while GES is a sample of all police-reported crashes not limited to passenger vehicle towaway crashes. GES is a better source to provide national statistics on nonfatal crashes in U.S. Therefore, the injury numbers then were adjusted to 1999 GES CDS-equivalent levels. The crash severity and injured body region percentage distribution are based on 1993-2000 CDS. Similarly, the corresponding fatalities and injuries were adjusted to the 1999 FARS and 1999 GES CDS-equivalent level, respectively.

GES does not include clock impact direction as does FARS and CDS, thus the analysis does not use frontal crashes in GES for injury adjustment. Instead, all the injuries in the GES CDS-equivalent crashes, regardless of crash types, were used in the injury adjustment process. The injury adjustment factor, for each pre-specific age group, from CDS to the GES CDS-equivalent level is the ratio between the passenger vehicle occupants in GES CDS-equivalent crashes and in CDS crashes, i.e.,






A. Problem Size

Annually, about 573 child passenger vehicle occupants age 0 to 12 years old are fatally injured in the front or rear seats in frontal crashes. In 1999, 100 of these fatally injured children were in a child restraint system (CRS). Eighty-two (14 percent) of these fatalities were in a properly used CRS when this crash occurred: 16 were in the front seats and 66 were in the rear seats. Eighteen were in an improperly used CRS. Table II-1 summarizes the child occupant fatalities in frontal crashes by age groups, restraint use, and seating position. Note that the restraint use was based on the 1999 FARS. The rear seats include the second, third, and fourth row seats.

In addition to fatalities, frontal crashes are also associated with 8,916 MAIS ⁽³⁾ 2-5 and 95,517 MAIS 1 non-fatal injuries, annually. Tables II-2 and II-3 report these child MAIS 2-5 and MAIS 1injuries, respectively, by age groups, restraint use, and seating position. As shown in these two tables, about 1,800 (20 percent) MAIS 2-5 and 19,289 (20 percent) MAIS 1 injuries were in a properly used CRS when the frontal crash occurred. The injuries were derived from 1993-2000 CDS and then adjusted to the 1999 GES CDS-equivalent level. The adjustment is achieved by multiplying the adjustment factor as described previously to the annualized injuries from 1993-2000 CDS. CDS did not record whether the child safety was used properly no not as did in FARS. The improperly used CRS in CDS was defined as that the child safety seat orientation was used not according to the manufacturer's designed orientation use.

Table II-1 Child Occupant Fatalities in Frontal Crashes
By Seating Position, Age, and Restraint Use

Age (Years Old)	Child Restraint System*	Improperly Used CRS	Belted	Not Belted	Total
Front Seats
0-1	15	3	3	28	49
2-3	1	1	8	29	39
4-6	0	0	19	36	55
7-10	0	0	31	40	71
11-12	0	0	11	27	38
Total	16	4	72	160	252
Rear Seats
0-1	31	9	5	18	63
2-3	28	4	4	28	64
4-6	6	1	32	34	73
7-10	1	0	33	60	94
11-12	0	0	11	16	27
Total	66	14	85	156	321
Front + Rear Seats
0-1	46	12	8	46	112
2-3	29	5	12	57	103
4-6	6	1	51	70	128
7-10	1	0	64	100	165
11-12	0	0	22	43	65
Total	82	18	157	316	573

Source: 1999 Fatality Analysis Reporting System
* Properly used CRS

Table II-2 Child Occupant Non-Fatal MAIS 2-5 Non-Fatal Injuries in
Frontal Crashes By Seating Position, Age, and Restraint Use

Age (Years Old)	Child Restraint System*	Improperly Used CRS	Belted	Not Belted	Total
Front Seats
0-1	419	0	142	151	712
2-3	30	0	308	96	434
4-6	35	0	200	942	1177
7-10	0	0	787	291	1078
11-12	0	0	208	225	433
Total	484	0	1645	1705	3834
Rear Seats
0-1	479	10	92	124	705
2-3	791	8	40	172	1011
4-6	46	0	528	337	911
7-10	0	0	882	848	1730
11-12	0	0	631	94	725
Total	1316	18	2173	1575	5082
Front + Rear Seats
0-1	898	10	234	275	1417
2-3	821	8	348	268	1445
4-6	81	0	728	1279	2088
7-10	0	0	1669	1139	2808
11-12	0	0	839	319	1158
Total	1800	18	3818	3280	8916

Source: 1999 General Estimated System (GES); 1993-2000 Crashworthiness Data System (CDS)
Note: MAIS 2-5 Injuries were derived from 1993-2000 CDS and adjusted to 1999 GES CDS-equivalent level.
*Properly used CRS

Table II-3 Child Occupant Non-Fatal MAIS 1 Injuries in Frontal Crashes
By Seating Position, Age, and Restraint Use

Age (Years Old)	Child Restraint System*	Improperly Used CRS	Belted	Not Belted	Total
Front Seats
0-1	1456	237	781	782	3256
2-3	2607	109	1270	395	4381
4-6	186	0	7706	1392	9284
7-10	0	0	9467	3867	13334
11-12	0	0	4928	2894	7822
Total	4249	346	24152	9330	38077
Rear Seats
0-1	4946	4753	231	1616	11546
2-3	7620	317	1716	1072	10725
4-6	2474	0	5234	1808	9516
7-10	0	0	14279	3796	18075
11-12	0	0	3713	3865	7578
Total	15040	5070	25173	12157	57440
Front + Rear Seats
0-1	6402	4990	1012	2398	14802
2-3	10227	426	2986	1467	15106
4-6	2660	0	12940	3200	18800
7-10	0	0	23746	7663	31409
11-12	0	0	8641	6759	15400
Total	19289	5416	49325	21487	95517

Source: 1999 General Estimated System (GES); 1993-2000 Crashworthiness Data System (CDS)
Note: MAIS 1 Injuries were derived from 1993-2000 CDS and adjusted to 1999 GES CDS- equivalent level.
* Properly used CRS

B. Children in CRS

Of particular interest for the analysis are the children in a CRS when the crash occurred. Table II-4 shows the children in a CRS by seating position and orientation of the CRS. Of all the 16 child occupant fatalities in the front seat, 9 were in a forward-facing CRS and 7 were in a rear-facing CRS. Of the 66 rear-outboard child occupant fatalities, 52 were in a forward-facing CRS and 14 were in a rear-facing CRS. As expected, all the fatalities and injuries for children age 2 and older sitting in the rear seat were in a forward-facing CRS.

As for MAIS 2-5 injuries, about 322 front seating children were in a forward-facing CRS and 162 were in a rear-facing CRS. Of the 1,316 rear seating MAIS 2-5 child injuries, 1,102 were in forward-facing CRS and 214 were in the rear-facing CRS.

Table II-4 Children in Properly Used Child Restraint System (CRS)
by Age, Seating Position, and Orientation of the CRS

Age (Years Old)	Front Seats			Rear Seats
	Forward Facing	Rear Facing	Total	Forward Facing	Rear Facing	Total
Fatalities
0-1	9	6	15	17	14	31
2-3	0	1	1	28	0	28
4-6	0	0	0	6	0	6
7-10	0	0	0	1	0	1
11-12	0	0	0	0	0	0
Total	9	7	16	52	14	66
MAIS 2-5 Injuries
0-1	257	162	419	265	214	479
2-3	30	0	30	791	0	791
4-6	35	0	35	46	0	46
7-10	0	0	0	0	0	0
11-12	0	0	0	0	0	0
Total	322	162	484	1102	214	1316
MAIS 1 Injuries
0-1	1342	114	1456	3386	1560	4946
2-3	2607	0	2607	7620	0	7620
4-6	186	0	186	2474	0	2474
7-10	0	0	0	0	0	0
11-12	0	0	0	0	0	0
Total	4135	114	4249	13480	1560	15040

Source: 1999 Fatality Analysis Reporting System; 1999 General Estimated System (GES); 1993-2000 Crashworthiness Data System (CDS)
Note: MAIS 1-6 Injuries were derived from 1993-2000 CDS and adjusted to 1999 GES-CDS equivalent level.

C. Relevant Statistics

The section presents statistics by crash severity (measured by Delta-V) and injured body region. The majority of the MAIS 1 injuries were skin bruises. We believe the effectiveness of the new proposal for these injuries would be minimal. Thus, the analysis focuses on fatalities and MAIS 2-5 non-fatal injuries. Due to small sample sizes, the statistics are for all children regardless of age, seating position, and restraint use.

Statistics by Crash Severity

As shown in Table II-5, about 60 percent of child fatalities and 90 percent of MAIS 2-5 injuries in frontal crashes occurred at impact speeds less than or equal to 30 mph. Note that the percentage distribution in Table II-5 was based on the 1993-2000 CDS. CDS is the only crash database that contains the Delta-V information.

Table II-5 All Child MAIS 2+ Occupant Injuries by Crash Severity
Regardless of Restraint Use

Injury Severity Frequency Percent	Crash Severity (Delta-V in MPH)
	0-20	21-30	31-40	41+	Total
Fatality	162 28%	173 32%	119 21%	119 21%	573 100%
MAIS 2-5 Injuries	5260 59%	2764 31%	713 8%	179 2%	8916 100%

Source: 1999 Fatality Analysis Reporting System; 1999 General Estimated System (GES); 1993-2000 Crashworthiness Data System (CDS)
Note: MAIS 2-5 Injuries were derived from 1993-2000 CDS and adjusted to 1999 GES-CDS equivalent level.

Statistics by Injured Body Region

Table II-6 shows the child MAIS 2+ passenger vehicle occupant injuries by MAIS injured body region. Head is the predominate injury body region. Neck injuries were rare occurrences. Due to small sample sizes and unknown injured body regions for fatalities, the percentages derived from MAIS 4-5 and fatalities combined were applied to fatalities. The statistics were based on 1993-2000 CDS. CDS is the only data system used in the analysis that records the injured body region.

Table II-6 All Child MAIS 2+ Injuries by MAIS and Body Region
Regardless of Restraint Use

Injury Severity Frequency Percent	MAIS Injured Body Region
	Head	Neck	Chest	Other*	Total
Fatality	407 71%	6 1**%	40 7%	120 21%	573 100%
MAIS 2-5 Injuries	3834 43%	18 0**%	535 6%	4529 51%	8916 100%

* Including abdomen, spine, upper extremity, and lower extremity
** Very small sample
Source: 1999 Fatality Analysis Reporting System; 1999 General Estimated System (GES); 1993-2000 Crashworthiness Data System (CDS)
Note: MAIS 2-5 Injuries were derived from 1993-2000 CDS and adjusted to 1999 GES-CDS equivalent level.

Based on Table II-6, head, neck, and chest comprised about 79 percent of fatalities and 49 percent of all MAIS 2+ injuries. Table II-7 shows the properly used child safety seat occupants with a fatal/MAIS 2-5 head, neck, or chest injuries regardless of seating position. These numbers were about 79 and 49 percent of fatalities and MAIS 2-5 injuries, respectively, in Table II-4.

Table II-7 Children in Properly Used Child Restraint Systems (CRS)
With a Fatal or MAIS 2-5 Head, Neck, or Chest Injury

Age (years Old)	Forward-Facing CRS	Rear-Facing CRS	Total
Fatalities
0-1	21	16	37
2-3	22	0	22
4-6	5	0	5
7-10	1	0	1
11-12	0	0	0
Total	49	16	65
MAIS 2-5 Injuries
0-1	256	184	440
2-3	402	0	402
4-6	40	0	40
7-10	0	0	0
11-12	0	0	0
Total	698	184	882

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¹ In some cases, the broader range of ages is needed to get a reasonable estimate of injuries by body region.
² General Estimates System Coding Manual 1999.
³ Maximum Abbreviated Injury Scale, 1-Minor Injury, 2-Moderate Injury, 3-Serious Injury, 4-Severe Injury, 5-Critical Injury. Only one injury with the most severity is counted per occupant.