US Department

ot Transportation

National Highway

Traffic Safety

Administration

DOT HS 807 371 December 1988

NHTSA Technical Report

Lives Saved by Child Restraints

from 1982 through 1987

This document is available to the public from the National Technical Information Service, Springfield, Virginia 22161
The United States Government does not endorse products {.

or manufacturers. Trade or manufacturers1 names appear

only because they are considered essential to the object

of this report. . •
Technical Report Documentation Page

1. Report No.

DOT HS 807 371

2. Government Accession No.

4. Title and Subtitle

Lives Saved by Child Restraints

from 1982 through 1987

7. Author's)

Susan C. Partyka

9. Performing Organization Name and Address

National Center for Statistics and Analysis

400 7th Street S.W.

Washington, D.C. 20590

12. Sponsoring Agency Nome and Address

Research and Development

National Highway Traffic Safety Administration

400 7th Street S.W.

Washington, D.C. 20590

3. Recipient's Catalog No.

5. Report Date

December 1988

6. Performing Organization Code

8. Performing Organization Report No.

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

13. Type of Report and Period Covered

NHISA Technical Report

1982-1987

Sponsoring Agency Code

15. Supplementary Notes

16. Abstract

Estimates derived from the Fatal Accident Reporting System (FARS) indicate that

restraints are very effective in preventing infant (under one year old) and toddler

(one through four: years old) fatalities. It is estimated that fatality reductions

from restraint use between 1982 and 1987 were:

69 percent for infants in child safety seats,

47 percent for toddlers in child safety seats, and

36 percent for toddlers in adult belts.

Because many restraints are incorrectly or incompletely used (as reported from

detailed observation surveys), potential effectiveness is probably higher than the

estimates provided here.

As child restraint use has increased, the annual number of lives saved has also

increased. Based on the methods described here, child safety seats and adult belts

used by infant and toddler passenger vehicle occupants saved an estimated:

75 lives in 1982,

105 lives in 1983,

126 lives in 1984,

153 lives in 1985,

166 lives in 1986, and

213 lives in 1987.

Child restraints could save many more lives, but use is still low in serious

accidents.

17. Key Words

accident data, child restraints,

fatalities

19. Security Classif. (of this report)

Unclassified

18. Distribution Statement

Document is available to the public

through the National Technical

Information Service,

Springfield, Virginia 22161

20. Security Classif. (of this page)

Unclassified

21. No, of Page*

22

22. Ptice

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

1
Estimates derived from the Fatal Accident Reporting System (EARS) indicate

that restraints are very effective in preventing infant (under one year old)

and toddler (one through four years old) fatalities. It is estimated that

fatality reductions from restraint use between 1982 and 1987 were:

69 percent for infants in child safety seats,

47 percent for toddlers in child safety seats, and

36 percent for toddlers in adult belts.

Because many restraints are incorrectly or incompletely used (as reported from

detailed observation surveys), potential effectiveness is probably higher than

the estimates provided here.

As child restraint use has increased, the annual number of lives saved has

also increased. Based on the methods described here, child safety seats and

adult belts used by infant and toddler passenger vehicle occupants saved an

estimated:

75 lives in 1982,

105 lives in 1983,

126 lives in 1984,

153 lives in 1985,

166 lives in 1986, and

213 lives in 1987.

Child restraints could save many more lives, but use is still low in

serious accidents. Observations taken at shopping centers in nineteen cities

indicate that about 80 percent of young children (under five years old) who

visited these centers in 1987 were in child safety seats. In contrast, only

24 percent of young children who survived a fatal accident were in child

safety seats. Observations taken by individual states produce results that

vary widely between these two extremes. Despite the effectiveness of child

restraints and the widespread use of safety seats in some areas, children in

serious crashes are usually unprotected.

If all young children used child restraints, more lives could be saved.

With 100 percent use, child seats (with the mix of correct and incorrect use

during 1982 through 1987) could have saved an estimated:

369 lives in 1982,

380 lives in 1983,

355 lives in 1984,

378 lives in 1985,

405 lives in 1986, and

462 lives in 1987.

If child seats are to achieve anything like this potential, they must become

more available to children involved in serious crashes.

Ihe remainder of this report describes the data and methods on which these

conclusions are based.

- 1 -
Data

Between 1982 and 1987 there were 7,060 vehicles reported to FARS that met

the following three criteria. First, they were passenger cars built after

front seat lap and shoulder belts were required (model years 1974 and later).

Second, they had a driver for whom restraint use was reported. And third,

they had a young child passenger (under five years old) for whom restraint use

and type (adult belts or child safety seat) was reported. Hie definitions

used to select and classify these cases are described in Appendix Table A.

Method

This paper uses the matched-pairs technique described in detail by Leonard

Evans (for example, in "Driver Fatalities versus Car Mass Using a New Exposure

Approach," Accident Analysis and Prevention. Volume 16, Number 1, 1984) and

used by him in a variety of studies of fatal accidents. This technique has

been used in previous agency analyses of child restraints ("Restraint Use and

Fatality Risk for Infants and Toddlers," Susan Partyka, 1984; "An Evaluation

of Child Passenger Safety: The Effectiveness and Benefits of Safety Seats,"

Charles Kahane, 1986).

The idea is to compute fatality odds from FARS data and treat them as if

they were fatality rates. For example, there were 4,239 vehicles in which

neither the driver nor the child passenger was restrained. In these vehicles,

there were 1,341 driver fatalities and 1,290 child passenger fatalities, as

shown in Table 1. The ratio of child to driver fatalities was:

1,290 / 1,341 = 0.962.

There were also 910 vehicles in which the driver was unrestrained, but the

child passenger was in a child safety seat. There were 324 driver fatalities

and 156 child passenger fatalities in these vehicles. The ratio of child to

driver fatalities was:

156 / 324 = 0.481.

If these fatality odds are interpreted as fatality rates, they can be used

to estimate the effectiveness of child safety seats in vehicles with an

unrestrained driver. Children in safety seats were:

(0.962 - 0.481) / 0.962 = 50 percent

less likely to be killed than were the unrestrained children in these fatal

accidents. This result is shown in Table 2.

These estimates were made for each combination of driver and child

restraint use, separately for front and rear seats, and separately for infants

(those under one year old) and toddlers (those one through four years old),

They are interpreted here as estimates of the effectiveness of child safety

seats and adult belts in saving the lives of young children.

- 2 -
The method depends on three assumptions. First, that restraint use was

correctly reported for fatalities and survivors of fatal accidents. Second,

that unknown restraint use data were missing at random. And third, that the

exposure of young children to potentially-fatal crashes was adequately

represented by the number of fatalities among drivers of young children.

Ihe data were also used to estimate the incremental benefits of rear (as

opposed to front) seating for young children. For example, in vehicles with

both the driver and child restrained, the fatality odds were:

716 / 603 = 1.187 for children in the front seat and

466 / 590 = 0.790 for children in the rear seat.

If these fatality odds are treated like fatality rates, the safety benefit

of placing a young child in the rear seat can be estimated. Children in the

rear seat were:

(1.187 - 0.790) / 1»187 «• 33 percent

less likely to be killed than were children in the front seat, Ihis result is

shown in Table 3.

•Hie combinations of driver restraint use, child restraint use, and child

seating position produced multiple estimates of the effectiveness of adult

belts and child safety seats in preventing fatalities among children and

multiple estimates of the benefits of placing a child in the safer rear seat

In some cases there was good agreement among the estimates, but in others

there was remarkable scatter.

Average effectiveness estimates were computed by weighting individual

effectiveness estimates by a measure intended to reflect the relative

reliability of the individual estimates. Bue reliability of the estimates

usually was limited most by the small number of restrained children. So this

measure (the number of vehicles with both a driver fatality and a restrained

child passenger, used to calculate each individual estimate) was used to

produce the weighted average estimate.

For example, child safety seat effectiveness in the front seats of

passenger cars was estimated twice: once for vehicles with unrestrained

drivers, and again for vehicles with restrained drivers. This produced

estimates that child safety seats were 58 percent and 34 percent effective,

respectively, in preventing fatality. One first estimate was based on data

that included 114 vehicles with both a child in a child safety seat and an

unrestrained driver fatality. The second estimate was based ori data that

included 35 vehicles with both a child in a child safety seat and a restrained

driver fatality. Ine average of these estimates was computed as;

(58 percent * 114 vehicles) + (34 percent * 35 vehicles) ^ 52

(114 vehicles + 35 vehicles) • •

Using a different weighting factor (or using straight averaging) would

produce different results from the ones reported here, 'me estimates of the

benefits of rear (as opposed to front) seating are most sensitive to the

selection of the weighting factor because the effectiveness estimates produced

for various categories of driver and child restraint status varied so widely,

- 3 -
Ijiestrainb Effectiveness

Table 1 shows the available data for children under five years old — all

seating positions, those known to have been in the front seat, and those known

to have been in a rear seat. The seating position of seme young children was

not known. These children are included in the summary across all seats, but

not in either of the two known seat areas.

The fatality odds shown in Table 1 were used to compare the fatality

experiences of unrestrained children to the experiences of children using

child safety seats and adult seat belts. Young children in safety seats were

54 percent less likely to be killed than were unrestrained children. This

should not be interpreted as an estimate of child safety seat effectiveness

because of confounding differences between unrestrained and restrained

children., Children in rear seats and infants were more likely to be

restrained than were children in front seats and toddlers. The biasing

effects of these two differences can be removed statistically from the

fatality data.

The first difference noted above is that unrestrained children more often

rode in the front seat than in the rear seat, while children in safety seats

more often rode in the safer rear seat. Because the rear seat is more

protective, this difference produces a statistical bias in favor of child

safety seats. To compensate for this difference, the data of Table 1 were

used to produce separate estimates of fatality reductions for front seat and

for rear seat occupants. <

It is estimated from these data that child safety seats are 52 percent

effective in preventing fatality in front seats and 47 percent effective in

preventing fatality in rear seats (Table 2). The difference between these two

estimates appears small enough to have resulted from chance. The weighted

average of these two estimates is 49 percent. This is the estimated

effectiveness of child safety seats in preventing fatality, controlling for

differences in seating position between unrestrained children and children in

safety seats.

Similar calculations produce an estimate that adult belts are 44 percent

effective in preventing fatality, after controlling for seating position

differences between unrestrained and belted children.

The data in Table 1 can also be used to compare the fatality odds of

children in the front and rear seats, after controlling for driver and child

restraint type. Table 3 shows that, on average, a young child was 26 percent

less likely to be killed in a rear seat than in the front seat. However,

there were large differences in the estimates produced by the various

categories of driver and child restraint status. At this time, there appears

to be no pattern in the variety of estimates. The variation may reflect

reporting biases, the inherent variability of the data, or a physical process

that is not yet understood.

- 4 -
Table 1: Fatalities of Drivers and their Young Child Passengers

(Children Under Five Years Old, 1982-1987 Data)

Child's

Position

* All Seats

Front

Rear

Pestraint Used bv

Driver

None

None

None

Belts

Belts

Belts

None

None

None

Belts

Belts

Belts

None

None

None

Belts

Belts

Belts

Child

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

Number of

Driver

1,341

84

324

60

87

178

603

28

114

23

34

35

590

54

197

34

49

135

Deaths

Child

1,290

42

156

120

88

137

716

14

57

44

39

44

466

28

99

63

46

92

Ratio of Fatalities

Driver/

Child

1.040

2.000

2.077

0.500

0.989

1.299

0.842

2.000

2.000

0.523

0.872

0.795

1.266

1.929

1.990

0.540

1.065

1.467

Child/

Driver

0.962

0.500

0.481

2.000

1.011

0.770

1.187

0.500

0.500

1.913

1.147

1.257

0.790

0.519

0.503

1.853

0.939

0.681

* Children with unknown seat position included in "All Seats."

Table 2: Estimated Percentage Benefits of Restraint Use by Young Children

Child Restrained by

Adult seat belt

Child safety seat

Control Used

Unrestrained driver

Restrained driver

Average

Unrestrained driver

Restrained driver

Average

No Seat

Position Benefit in;

Control Front Rear

48 58 34

49 40 49

49 48 41

50

62

54

58

34

52

36

63

47

Average

Benefit

42

46

44

44

57

49

Table 3: Estimated Percentage Benefits of Rear Seating for Young Children

within Categories of Driver and Child Restraint Use

Restraint Use of Driver Control

Child Restrained by

None

Adult seat belt

Child safety seat

Average

Unrestrained

33

-4

=1

25

Restrained 1

3

18

46

31

Vveraqe

32

7

16

26

- 5 -
The second difference between unrestrained and restrained children noted

previously is that infants were more frequently restrained (especially in a

child safety seat) than were toddlers. Because infants are more vulnerable to

injury than are older children, this difference produces a statistical bias

against child safety seats. To compensate for this difference, the data of

Table 1 for all young children were separately tabulated for infants (Table 4)

and toddlers (Table 7). The data from these two tables were used to produce

separate estimates of fatality reductions for infants and toddlers, for front

and for rear seat occupants.

The separate calculations performed are summarized for infants (those

under one year old) in Tables 4 through 6 and for toddlers (those one through

four years old) in Tables 7 through 9. The data for adult-belted infants are

inadequate for meaningful estimates. The estimated fatality reductions from

restraint use (controlling for differences in seat positions of unrestrained

and restrained children) are:

69 percent for infants in child safety seats,

47 percent for toddlers in child safety seats, and

36 percent for toddlers in adult belts.

In each case, accounting for differences in seating positions of unrestrained

versus restrained children produces estimated fatality benefits that are

between three and five percentage points lower than the estimates produced

without adjusting for this difference.

The estimated average benefit of sitting in a rear seat was 29 percent for

infants and 19 percent for toddlers. For infants, the estimated benefits were

higher for cases with a restrained driver but did not seem to depend on the

restraint status of the child. The estimates derived for toddlers varied

widely, depending on the restraint status of the driver and of the toddler.

The reasons for these differences are not currently understood.

- 6 -
Table 4: Fatalities of Drivers and their Infant Passengers

(Children Under One Year Old, 1982-1987 Data)

Child's

Position

* All Seats

Front

Rear

Restraint Used bv

Driver

None

None

None

Belts

Belts

Belts

None

None

None

Belts

Belts

Belts

None

None

None

Belts

Belts

Belts

Child

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

Number of

Driver

196

3

99

3

5

42

122

3

38

1

4

9

53

0

57

2

0

32

Deaths

Child

332

2

58

26

7

44

237

1

28

11

5

14

76

1

30

11

1

30

Ratio of Fat

Driver/

Child

0.590

1.500

1.707

0.115

0.714

0.955

0.515

3.000

1.357

0.091

0.800

0.643

0.697

0.000

1.900

0.182

0.000

1.067

:alitie

Child/

Driver

1.694

0.667

0.586

8.667

1.400

1.048

1.943

0.333

0.737

11.000

1.250

1.556

1.434

-

0.526

5.500

-

0.938

* Children with unknown seat position included in "All Seats."

Table 5: Estimated Percentage Benefits of Restraint Use by Infants

Child Restrained by Oontrol Used

Child safety seat Unrestrained driver

Restrained driver

Average

No Seat

 r

Position Benefit in; Average

Oontrol Front Rear Benefit

65 62 63 63

88 86 83 84

72 67 70 69

Table 6: Estimated Percentage Benefits of Rear Seating for Infants

with Categories of Driver and Child Restraint Use

Child Restrained by

None

Child safety seat

Average

Restraint Use of Driver Oontrol

Unrestrained Restrained Average

26 50 27

29 4Q 32

27 40 29

- 7 -
Table 7: Fatalities of Drivers and their Toddler Passengers

(Children One through Four Years Old, 1982-1987 Data)

Child's*

position

All Seats

Front

Rear

Restraint Used bv

Driver

None

None

None

Belts

Belts

Belts

None

None

None

Belts

Belts

Belts

None

None

None

Belts

Belts

Belts

Child

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

None

Adult belt

Child seat

Number of

Driver

1,145

81

225

57

82

136

481

25

76

22

30

26

537

54

140

32

49

103

Deaths

Child

958

40

98

94

81

93

479

13

29

33

34

30

390

27

69

52

45

62

Ratio of

Driver/

Child

1.195

2.025

2.296

0.606

1.012

1.462

1.004

1.923

2.621

0.667

0.882

0.867

1.377

2.000

2.029

0.615

1.089

1.661

Fatalities

Child/

Driver

0.837

0.494

0.436

1.649

0,988

0.684

0.996

0.520

0.382

1.500

1.133

1.154

0.726

0.500

0.493

1.625

0.918

0.602

* Children with unknown seat position included in "All Seats."

Table 8: Estimated Percentage Benefits of Restraint Use by Toddlers

Child Restrained by

Adult seat belt

Child safety seat

Control Used

Unrestrained driver

Restrained driver

Average

Unrestrained driver

Restrained driver

Average

No Seat

Position

Control

41

40

41

48

59

52

Benefit.

Front }

48

24

35

62

23

52

in:

tear

31

43

37

32

63

45

Average

Benefit

36

36

36

43

55

47

Table 9: Estimated Percentage Benefits of Rear Seating for Toddlers

within Categories of Driver and Child Restraint Use

Child

None

Adult seat belt

Child safety seat

Average

Restraint Use of Driver Control

Unrestrained Restrained Average

27

4

17

-8

19

48

28

25

11

_Q

19

mm D «,»
Lives Saved by Restraints

Appendix Table B shows cxunts of young childrem killed as occupants of

passenger vehicles (cars, pickups, vans, and multipurpose vehicles) by

accident year, age, and reported restraint use. For each row of this table,

the unknown data were prorated among the known data in two steps. First,

fatalities with unknown restraint use were prorated between fatalities in

child seats and adult seat belts. And second, fatalities for whom it was not

known whether or not they were restrained were prorated across the resulting

estimates of fatalities in child seats and in adult belts and fatalities

reported as unrestrained. The results are shown in Appendix Table C.

The estimates of Appendix Table C were collapsed to produce estimates of

restraint use by fatally-injured infants and toddlers, shown in Table 10. It

is estimated that in 1982 there were 48 young children killed in a child

safety seat (7.8 percent of young children killed in passenger vehicles that

year). In 1987, there were an estimated 135 young children killed in a safety

seat (20.6 percent of young child occupants killed that year).

Table 10: Estimated Type of Restraint Used by Fatalities

Categorized into Infants and Toddlers

Year

1982

1983

1984

1985

1986

1987

1982

-87

Age

0

1=4.

0-4

0

1=4

0-4

0

1=4

0-4

0

1=4

0-4

0

1=4

0-4

0

1=5

0-4

0

1-4

0-4

Estimated Fatality Counts

None

Used

145

407

552

130

387

517

103

325

428

94

,327

421

91

347

438

113

333

446

676

2.126

2,802

Child

Seat

19

29

48

26

42

68

28

55

83

34

_67

101

33

_67

100

39

135

179

156

535

Adult

Belt

0

13

13

1

16

17

1

25

26

2

30

32

6

55

61

6

67

73

16

206

222

164

449

613

157

445

602

132

405

537

130

424

554

130

469

599

158

496

654

871

2.688

3,559

Estimated Percent Use

Child

Seat

11.6

,6*5

7.8

16.6

-9*4

11.3

21.2

13.6

15.5

26.2

15.8

18.2

25.4

14*3

16.7

24.7

19.4

20.6

20.6

13.2

15.0

Adult

Belt

0.0

2*9

2.1

0.6

3.6

2.8

0.8

6*2

4.8

1.5

2*1

5.8

4.6

10.2

3.8

11,5

11.2

1.8

2/Z

6.2

Total

Use

11.6

-2*4

10.0

17.2

13.0

14.1

22.0

19.8

20.3

27.7

22.9

24.0

30.0

26.0

26.9

28.5

32.9

31.8

22.4

20.9

21.3

- 9 -
Ihese estimates of young restrained children killed in passenger vehicles

were combined with the restraint effectiveness estimates produced in the

previous section, to form estimates of lives saved by restraints. The

estimated effectiveness of adult belts in preventing toddler fatality was used

as the estimate for infants; a separate infant estimate could not be derived

from the few available cases of adult-belted infants.

Child restraint benefits were calculated as:

Lives Saved « Vitalities * ^straint Effectiveness .

1 - Restraint Effectiveness

The results are shown in Table 11.

Table 11: Estimated Young Children Saved by Restraints

Estimated

Restrained

Fatalities

1982

1983

1984

1985

1986

1987

1982-1987

Estimated

Percent

Fatality

Reduction

Estimated

THVPR Saved

1982

1983

1984

1985

1986

1987

1982-1987

]

Adult

Belt

0

1

1

2

6

6

16

0.36

0

1

1

1

3

3

9

[nfants

Child

Seat

19

26

28

34

33

-39

179

0.69

42

58

62

76

73

87

398

Total

Use

19

27

29

36

39

_45

195

—

42

59

63

77

76

90

407

Toddlers

Adult

Belt

13

16

25

30

55

_62

206

0.36

7

9

14

17

31

38

116

Child

Seat

29

42

55

67

67

_96

356

0.47

26

37

49

59

59

85

315

Total

Use

42

58

80

97

122

163

562

—

33

46

63

76

90

123

431

Infants + Toddlers

Adult

Belt

13

17

26

32

61

73

222

-

7

10

15

18

34

41

125

Child

Seat

48

68

83

101

100

135

535

—

68

95

111

135

132

172

713

Total

Use

61

85

109

133

161

208

757

-

75

105

126

153

166

213

838

This procedure produces an estimate that 213 young child occupants of

passenger vehicles were saved by restraint use in 1987 — 172 in child safety

seats and 41 in adult belts. Between 1982 and 1987, child safety seats saved

an estimated 713 lives. Adult belts saved an additional 125 lives, for a

total of 838 young children saved by restraints in these six years.

- 10 -
Potential Lives Saved by Restraints

If all young children had been using a child safety seat, more lives could

have been saved. Estimates of the number savable each year were calculated

from total fatalities (Table 10), lives saved by restraints (Table 11), and

effectiveness of restraints as used during these six years, as follows:

Infant Lives That Could Be Saved

= (Total Fatalities + Lives Saved) * 0.69, and

Toddler Lives That Could Be Saved

= (Total Fatalities + Lives Saved) * 0.47.

At these effectiveness levels, safety seats could have saved an average of

400 lives a year. The potential benefits depend on the number of children

involved in accidents each year and the mix of infants (for whom child safety

seats are very effective) and toddlers (for whom effectiveness has been lower,

perhaps because of more frequent incorrect use). The estimates are shown in

Table 12.

More young children are being saved each year because of increased child

seat use in serious crashes. In 1982, about one-fifth of the lives that could

be saved with 100 percent use of child restraints were saved. By 1987, close

to one-half of the potential lives saved (given the actual mix of correct and

incorrect use modes) were actually saved. The data are shown in Table 13.

Table 12: Estimates of Lives Savable by Child Seats

as Used during 1982 through 1987

Year

1982

1983

1984

1985

1986

1987

Total

Infants

142

149

135

143

142

121

882

Toddlers

227

231

220

235

263

291

1,466

Total

369

380

355

378

405

462

2,348

Table 13: Young Children Saved by Restraints

as a Percentage of Those Savable,

with Restraints as Used during 1982 through 1987

Year Infants Toddlers Total

1982

1983

1984'

1985

1986

1987

Total

30 %

40 %

47 %

54 %

54 %

53 %

46 %

15 %

20 %

29 %

32 %

34 %

42 %

29 %

20 %

28 %

35 %

40 %

41 %

46 %

36 %

- 11 -
Discussion

These estimates of restraint effectiveness for young children depend on

three assumptions. First, that restraint use was correctly reported for young

children and their drivers in fatal accidents. Second, that the unknown data

on restraint use and type were missing at random. And third, that driver

fatalities in passenger vehicles with young child occupants were an adequate

exposure measure for the risks of death to young children.

It is not possible to test these assumptions directly. However, it seems

that unrestrained people reported as restrained (the issue of the first

assumption) would be more common for adult belts (whether used by drivers or

by children) than for child seats. The presence of a child seat, if not the

child in the seat and the correctness of its use, is obvious. The device has

been bought specially, presumably because the child's parent believes in

either its value or its legal necessity. In contrast, adult belts are

standard in all passenger vehicles. Their presence in the vehicle does not

indicate a committment to their use.

Unknown restraint use data (the issue of the second assumption) frequently

reflects the police accident report form used in a particular state. Some

states do not routinely report restraint use (there is no restraint use data

element on the police report) or do not routinely report restraint type used

(the restraint use data element includes only codes for yes and no). In these

states, restraint use or restraint type is reported to FARS only if the police

officer described it in the narrative portion of the police report. These

unknown data resemble the known data on the FARS file to the extent that

restraint use in these states resembles restraint use in states with more, or

more-detailed, restraint use coding.

The adequacy of driver fatalities as a measure of child fatality risk (the

issue of the third assumption) is unclear. It is possible that child

restraints prevent fatalities in crashes that pose little risk to the driver.

If child restraints are most effective in low-severity crashes (for example,

by preventing ejections of small people through open windows), then this

estimation method underestimates the value of child restraints. Lives saved

by child seats will not be reported to FARS unless someone else in the

accident dies. If this is the case, the estimates provided here may be better

described as the effectiveness of child restraints in high-severity accidents.

As a check of the process as a whole, the data of Table 1 were used to

calculate car driver seat belt effectiveness (with child fatalities as the

standardizing factor). The results are shown in Table 14.

Table 14: Effectiveness of Seat Belts for Car Drivers

(Percentage Fatality Reduction)

Child's Seat Position in Car

Control Used

Unrestrained child

Adult belted child

Child seated child

Average

Overall

52

51

32

47

Front

38

56

60

51

Rear

57

45

26

43

Averaqe

48

51

43

47

- 12 -
This method produced an estimate that driver seat belts were 47 percent

effective in preventing driver fatality (on average, across the three

categories of child restraint status). Individual estimates varied from 43

percent (for drivers with children in safety seats) to 48 percent (for drivers

of unrestrained children) to 51 percent (for drivers with children in adult

belts). These are within the agency's estimated range (40 to 50 percent) of

lap and shoulder belt effectiveness.

There is a problem in reconciling the child restraint benefits (realized

and potential) estimated here with the prevalent child safety seat use

reported in some observation surveys. It is estimated that 213 children were

saved by restraints in 1987, but that 462 could have been saved if all young

children had used child safety seats. Ihis implies that many children were

unrestrained in accidents. Table 15 shows (based on the detailed data in

Appendix Tables D and E) that it is estimated that only a half of all young

children who survived a fatal traffic accident were using any kind of

restraint in 1987.

Table 15: Estimated Type of Restraint Used by Survivors of Fatal Accidents

Categorized into Infants and Toddlers

Year

1982

1983

1984

1985

1986

1987

1982

-87

Age

0

1=4

0-4

0

1=4

0-4

0

1=4

0-4

0

1=4

0-4

0

1-4

0-4

0

1=4

0-4

0

1-4

0-4

Estimated Fatalitv Counts

None

Used

173

1.267

1,440

154

1,155

1,309

130

1.007

1,137

97

967

1,064

127

935

1,062

125

944

1,069

806

6.275

7,081

Child

Seat

55

_9§

150

86

241

327

119

315

434

135

393

528

133

430

563

156

496

652

684

1.970

2,654

Adult

Belt

5

66

71

4

83

87

1

135

136

8

187

195

8

318

326

6

412

418

32

1.201

1,233

Total

233

1.428

1,661

244

1.479

1,723

250

1.457

1,707

240

1.547

1,787

268

1.683

1,951

287

1.852

2,139

1,522

9.446

10,968

Estimated Percent Use

Child

Seat

23.6

_6/7

9.0

35.2

16.3

19.0

47.6

21.6

25.4

56.3

25.4

29.5

49.6

25.5

28.9

54.4

26.8

30.5

44.9

20.9

24.2

Adult

Belt

2.1

4^6

4.3

1.6

5*6

5.0

0.4

9^3

8.0

3.3

12.1

10.9

3.0

18.9

16.7

2.1

22.2

19.5

2.1

12.7

11.2

Total

Use

25.8

11.3

13.3

36.9

21.9

24.0

48.0

30.9

33.4

59.6

37^5

40.5

52.6

44.4

45.6

56.4

49.0

50.0

47.0

33.6

35.4

- 13 -
In contrast, observations taken by the agency's 19-Cities Survey (managed

by the Office of Driver and Pedestrian Research) indicate that restraint use

near the dhcppJr»g centers included in the survey was much higher. By 1987,

the survey was reporting that four-fifths of young children (both infants and

toddlers) were restrained.

Differences between infants and toddlers have disappeared in the survey

data. In 1981, twice as many infants as toddlers were using child restraints:

40.4 percent of those under one year old, compared to only 19.4 percent of

those aged one through four years old. By 1987, approximately four-fifths of

each age group were observed using child restraints: 77.5 percent of those

under one year old and 80.1 percent of those aged one through four years. Ihe

uniformly high child restraint use rates reported from observation surveys

appear to conflict with the lower use rates reported for children (especially

toddlers) in fatal accidents. Ihe data for infants and for toddlers are shown

in Tables 16 and 17, respectively.

Table 16: Changes in Infant Use of Child Restraints

Year

1982

1983

1984

1985

1986

1987

19-Cities

n/a

60.4

66.4

66.4

70.0

77.5

FARS Fatal

Survivors

23.6

35.2

47.6

56.3

49.6

54.4

Accidents

Fatalities

11.6

16.6

21.2

26.2

25.4

24.7

Table 17: Changes in Toddler Use of Child Restraints

Year

1982

1983

1984

1985

1986

1987

19-Cities

n/a

37.8

44.3

52.6

72.3

80.1

FARS Fatal

Survivors

6.7

16.3

21.6

25.4

25.5

26.8

Accidents

Fatalities

6.5

9.4

13.6

15.8

14.3

19.4

Table 18: Changes in Toddler Use of Adult Restraints

Year

1982'

1983

1984

1985

1986

1987

19-Cities

n/a

5.3

7.4

9.3

5.9

4.7

FARS Fatal

Survivors

4.6

5.6

9.3

12.1

18.9

22.2

Accidents

Fatalities

2.9

3.6

6.2

7.1

11.7

13.5

- 14 -
Large (and increasing) numbers of young children in fatal accidents were

reported to have been using an adult belt (Table 18). By 1987, 22.2 percent

of toddlers Who survived a fatal accident were reported to have been using an

adult belt. The accuracy of these data is not known. But even among toddler

fatalities (whose restraint reporting is believed to be more accurate), adult

belt use was reported as 13.5 percent in 1987. In contrast, even in recent

years few toddlers (4.7 percent in 1987) were observed in adult belts in

traffic near shopping centers.

Reported child restraint use in fatal accidents declined rapidly with the

age of the child. While high levels of restraint use were reported for those

under two years old, older children were less frequently reported to have been

restrained in the accident. Fewer than 10 percent of four year olds were

reported to have been using a child restraint in a fatal accident (whether the

child survived or was killed). The 1987 data are shown in Table 19. The

observation survey does not report the individual age of a toddler.

Table 19: Child Restraint Use in 1987, by Child Age

Age

0

1-4

0

1

2

3

4

19-Cities

77.5

80.1

77.5

n/a

n/a

n/a

n/a

FARS Fatal

Survivors

54.4

26.8

54.4

50.1

30.8

21.7

6.9

Accidents

Fatalities

24.7

19.4

24.7

32.6

24.2

13.5

5.3

The low child restraint use reported for three and four year olds in fatal

accidents (compared to the high use reported for younger children) suggests a

possible reporting problem. It may be difficult to estimate the age of older

toddlers under the observation conditions. A child in a child restraint may

more obviously be a toddler than the same child riding unrestrained or in an

adult belt. A particular child may look four years old when seated in a child

restraint, but look five years old when using an adult belt. However, traffic

observers used the same protocol in 1987 as in 1981, and many observers who

collected the earlier data also collected the more recent data.

Another possibility is that the children observed by the 19~Cities Survey

are not completely representative of children involved in serious accidents.

This may be for either of at least two reasons. First, children in the areas

surveyed may not adequately represent young children in traffic in all areas

of the country. And second, young children in traffic may not adequately

represent young children who became involved in serious accidents. These two

possibilities are discussed further below.

- 15 -
First, the 19-Cities Survey of young children is based near shopping

centers to increase the numbers observed. The survey may tend to include

people who can afford to buy child restraints and to exclude people who feel

they can only afford to put their children in the available adult seat belts.

People for whom child restraints are very expensive may tend to shop

elsewhere. Ihe result would be an overestimate of child restraint use in

traffic. Ihe cost of the child restraint may be a particular problem for

toddlers because they are less accessible to maternity-based information and

loaner programs than they were as newborns.

This possibility is partially supported by child restraint use reported by

individual states. Some states (such as California and North Carolina) report

high rates of child restraint use, comparable to the rates observed by the

19-Cities Survey. However, many other states report child restraint use rates

of less than 40 percent.

Second, it has been observed that adult restraint use in accidents is

lower than restraint use observed in traffic. It is likely that child

restraint use is also lower in serious accidents than it is in general

traffic. People who put young children in child restraints may tend to get

into fewer and less-serious accidents than people who drive with unrestrained

children. Ihe result would be optimistic estimates of child restraint use in

accidents from the observation data. Ihe unrestrained children in the

observation surveys may be at greater risk of becoming involved in a serious

accident than are the restrained children.

This possibility is partially supported by accident data. Restraint use

by children who survived a fatal accident in 1987 was slightly higher in urban

areas and during the day than in rural areas and at night. These conditions

of higher child restraint use correspond to 19-Cities Survey observation

conditions.

In summary, it appears clear than restraint use in accidents is much lower

than reported in observation surveys, particularly in the agency's 19-Cities

Survey. While child restraint use has increased over the last five years,

children in serious accidents are still all too often unprotected. This

situation is similar to that of the high risk adult population, who are less

likely to use safety belts than is the general population. Further fatality

reductions will require greater use of child safety seats where they are most

needed — in serious crashes.

- 16 -
Appendix Table A: Definitions

Category

Vehicle Type:

Passenger Vehicle

Passenger Car

Lap and Shoulder Belt Equipped

Driver

Driver Restraint Use:

Unrestrained

Restrained

Child Age:

Young Child

Infant

Toddler

Child Restraint Use:

Unrestrained

Adult Belted

Child Safety Seated

Child Seat Position:

Front Seat

Rear Seat

Occupant Outcome:

Killed

Survived

ERRS Data Element

Body Types 1-12, 40-41, 48-51,

53-56, 58-58, 67-69

Body Types 1-11, 67

Model Years 74-88

Seat Position 11 and Age 5-99

Manual Restraint 0 and

Automatic Restraint not 1 and

Automatic Restraint not 3

Manual Restraint 1-8 or

Automatic Restraint 1 or

Automatic Restraint 3

Age 0-4

Age 0

Age 1-4

Manual Restraint 0 and

Automatic Restraint not 1 and

Automatic Restraint not 3

(Manual Restraint 1-7 or

Automatic Restraint 1 or

Automatic Restraint 3)

and Manual Restraint not 4

Manual Restraint 4

Seat Positions 12-19

Seat Positions 21-49

Injury Severity 4

Injury Severity not 4

- 18 -
Appendix Table B:

totalities by Police-Reported Restraint Use

•Type Restraint

lt

yp

None Child Adult Unknown Unknown

Acje Used Seat ^Jelfc Type, if Used

1982 0 124 15 0 1 24

1 80 13 2 2 13

2 104 6 5 1 14

3 92 4 1 1 13

4 82 0 3 0 13

1983 0 117 23 1 0 16

1 95 17 3 3 4

2 98 10 2 1 8

3 87 6 7 2 12

4 77 2 1 0 10

1984 0 96 25 1 1 9

1 48 22 1 1 8

2 75 11 10 2 13

3 84 5 3 1 15

4 79 6 6 2 12

1985 0 85 29 2 2 12

1 63 23 4 0 3

2 83 23 13 2 7

3 84 8 1 2 9

4 71 5 8 1 13

1986 0 83 30 5 0 12

1 84 25 3 2 9

2 81 18 14 1 10

3 81 8 10 3 9

4 72 5 14 9 11

1987 0 109 35 5 3 6

1 75 36 7 5 10

2 69 25 17 4 9

3 89 15 12 1 9

4 75 5 22 2 10

1982 0 614 157 14 7 79

-87 1 445 136 20 13 47

2 510 93 61 11 61

3 517 46 34 10 67

4 456 23 54 14 69

All data as reported on FARS

- 19 -
Appendix Table C:

Fatalities by Estimated Restraint Use

Year

1982

1983

1984

1985

1986

1987

1982

-87

Age

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

Estimated

None

Used

145

91

117

104

95

130

98

105

97

87

103

53

85

98

89

94

65

88

92

82

91

91

88

88

80

113

81

74

96

82

676

479

557

575

515

Child

Seat

19

17

7

5

0

26

20

12

8

2

28

26

14

7

8

34

24

26

11

6

33

29

20

10

8

39

43

30

17

6

179

159

109

58

30

Use

Adult

Belt

0

3

6

1

3

1

4

2

9

1

1

1

12

4

8

2

4

15

1

10

6

3

16

13

23

6

8

20

13

26

16

23

71

41

71

Total

164

111

130

110

98

157

122

119

114

90

132

80

111

109

105

130

93

129

104

98

130

123

124

111

111

158

132

124

126

114

871

661

737

674

616

Estimated Percent Use

Child

Seat

11.6

15.3

5.4

4.5

0.0

16.6

16.4

10.1

7.0

2.2

21.2

32.5

12.6

6.4

7.6

26.2

25.8

20.2

10.6

6.1

25.4

23.6

16.1

9.0

7.2

24.7

32.6

24.2

13.5

5.3

20.6

24.1

14.8

8.6

4.9

Adult

Belt

0.0

2.7

4.6

0.9

3.1

0.6

3.3

1.7

7.9

1.1

0.8

1.3

10.8

3.7

7.6

1.5

4.3

11.6

1.0

10.2

4.6

2.4

12.9

11.7

20.7

3.8

6.1

16.1

10.3

22.8

1.8

3.5

9.6

6.1

11.5

Ttotal

Use

11.6

18.0

10.0

5.5

3.1

17.2

19.7

11.8

14.9

3.3

22.0

33.8

23.4

10.1

15.2

27.7

30.1

31.8

11.5

16.3

30.0

26.0

29.0

20.7

27.9

28.5

38.6

40.3

23.8

28.1

22.4

27.5

24.4

14.7

16.4

Data estimated by prorating "unknown restraint type" across known types

and "unknown whether or not restrained" across other restraint categories

within accident year and individual year of occupant age

- 20 -
Appendix Table D:

Survivors of Fatal Accidents, by Police-Reported Restraint Use

Type Restraint Used

Year

1982

1983

1984

1985

1986

1987

1982

-87

Age

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

None

Used

144

221

287

272

242

130

134

262

263

287

112

131

232

229

276

87

141

241

239

229

114

138

212

225

238

116

158

245

226

229

703

923

1,479

1,454

1,501

Child

Seat

45

37

25

5

7

70

83

56

32

14

95

112

81

44

16

116

139

81

65

28

117

160

105

60

21

135

183

125

77

22

578

714

473

283

108

Adult

Belt

4

17

9

10

16

3

10

10

16

28

1

7

28

36

36

7

10

36

54

43

7

17

56

82

90

5

32

62

89

122

27

93

201

287

335

Unknown

Type

1

2

1

2

0

3

4

4

2

3

8

8

10

8

4

6

16

11

10

20

2

15

18

14

18

10

11

23

33

49

30

56

67

69

94

Unknown

if Used

39

59

74

73

69

38

66

64

72

69

34

32

64

53

52

24

33

51

46

54

28

33

57

65

60

20

29

42

55

41

183

252

352

364

345

T

1,

2,

2,

2,

2,

ota]

233

336

396

362

334

244

297

396

385

401

250

290

415

370

384

240

339

420

414

374

268

363

448

446

427

286

413

497

480

463

521

038

572

457

383

All data as reported on FARS

- 21 -
Appendix Table E:

Survivors of Fatal Accidents, by Estimated Restraint Use

Year

1982

1983

1984

1985

1986

1987

1982

-87

Age

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

0

1

2

3

4

Estimated

None

Used

173

268

353

341

305

154

172

313

323

347

130

147

274

267

319

97

156

274

269

268

127

152

243

263

277

125

170

268

255

251

806

1,065

1,725

1,718

1,767

Child

Seat

55

47

32

7

9

86

111

71

41

18

119

134

105

56

20

135

171

101

79

42

133

191

134

77

28

156

207

153

104

32

684

861

596

364

149

Use

Adult

Belt

5

21

11

14

20

4

13

13

21

36

1

8

36

46

45

8

12

45

66

64

8

20

71

105

122

6

36

76

121

179

32

110

252

373

466

1

2

2

2

2

?tal

233

336

396

362

334

244

296

397

385

401

250

289

415

369

384

240

339

420

414

374

268

363

448

445

427

287

413

497

480

462

,522

,036

,573

,455

,382

Estimated Percent Use

Child

Seat

23.6

14.0

8.1

1.9

2.7

35.2

37.5

17.9

10.6

4.5

47.6

46.4

25.3

15.2

5.2

56.3

50.4

24.0

19.1

11.2

49.6

52.6

29.9

17.3

6.6

54.4

50.1

30.8

21.7

6.9

44.9

42.3

23.2

14.8

6.3

Adult

Belt

2.

6.

2.

3.

6.

1.

4.

3.

5.

9.

0.

2.

8.

12.

11.

3.

3.

10.

15.

17.

3.

5.

15.

23.

28.

2.

8.

15.

25.

38.

2.

5.

9.

15.

19.

1

3

8

9

0

6

4

3

5

0

4

8

7

5

7

3

5

7

9

1

0

5

8

6

6

1

7

3

2

7

,1

4

8

2

6

Total

Use

25.

20.

10.

5.

8.

36.

41.

21.

16.

13.

48.

49.

34.

27.

16.

59.

54.

34.

35.

28.

52.

58.

45.

40.

35.

56.

58.

46.

46.

45.

47,

47.

33.

30.

25.

8

2

9

8

7

9

9

2

1

5

0

1

0

6

9

6

0

8

0

3

6

1

8

9

1

4

8

1

9

7

,0

,7

,0

,0

,8

Data estimated by prorating "unknown restraint type" across known types

and "unknown whether or not restrained" across other restraint categories

within accident year and individual year of occupant age

- 22 -
US

. Department

of Transportation

National Highway

Traffic Safety

Administration

400 Seventh St, S W

Washington, D.C. 20590

Official Business

Penalty for Private Use $300

Postage and Fees Paid

National Highway

Traffic Safety

Administration

DOT 517