National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

1

U.S. Department 

Of Transportation 

National Highway 

Traffic Safety 

Administration

 DOT HS 809 697 Research Note December 2003 

Restraint Use of Large Truck Occupants Involved in Fatal Crashes 

Cejun Liu*

Introduction 

Every year, there are more than 600 deaths of 

large truck occupants in fatal motor vehicle 

crashes [1-2]. Restraint use by large truck 

occupants is of concern. In this work, restraint 

use of large truck drivers and passengers 

involved in fatal crashes is examined. 

Methodology 

In this research note, the occupant type includes 

driver, passenger and unknown occupant in a 

large truck. “Restraint use” is categorized as 

“used” (shoulder and lap belt, child safety seat 

or restraint type unknown), “not used” and 

“unknown”. Occupant is classified as a “fatality” 

or “survivor ” of the crash. Unknown injury 

severity cases are not included in this study. 

Data from the Fatality Analysis Reporting 

System (FARS) for the period 1988-2002 were 

used. The FARS database is a national census of 

police-reported motor vehicle crashes resulting 

in fatal injuries. It is conducted by the National 

Center for Statistics and Analysis (NCSA) in the 

National Highway Traffic Safety Administration 

(NHTSA). 

Results 

Table 1 and Table 2 show large truck occupants 

killed and survived, respectively, in fatal crashes 

by year, occupant type and reported restraint 

use. The data indicate that for occupants whose 

restraint use is known (i.e. excluding occupants 

whose restraint use is unknown), a high 

percentage of occupants killed in large truck 

crashes were not restrained: 75 percent of 

drivers and 91 percent of passengers regardless 

of locations (in passenger vehicles over the same 

time period, 1988-2002, 66 percent of drivers 

and 69 percent of passengers killed in crashes 

were unrestrained). A higher percentage of 

occupants who survived in fatal crashes were 

restrained than those who were killed. The data 

show an increase in the percentages of large 

truck occupants who were restrained from 1988 

through 2002 in fatal crashes. This feature is 

also graphically illustrated by Chart 1 to Chart 4. 

One may use survival status (killed or survived) 

as a dependent response variable, restraint use 

(restrained or unrestrained) and occupant type 

(driver or passenger) as independent variables to 

fit a logistic model in terms of total number for 

the period 1988-2002 (not including occupants 

where the restraint use is unknown). The results 

of the logistic analysis are in Table 3. 

 Table 3. Logistic Analysis 

 Maximum Likelihood Estimates 

 Parameter Estimate S.E. Pr > χ

2

 

 Intercept -3.112 0.0234 <0.0001 

 Occupant 

 (Passenger) -0.546 

 

 0.0332 <0.0001 

Restraint Use 

(Unrestrained) 2.241 

 

 0.0279 <0.0001 

 Odds Ratio Estimates 

 

 Effect 

 Point 

 Estimate 

 95%Wald 

Confidence Limits 

 Occupant 

 (Passenger 

 vs. Driver) 

 

 0.580 0.543 0.618 

 Restraint Use 

(Unrestrained 

vs. Restrained) 

 

 9.400 

 

 8.900 

 

 9.926 

The analysis shows that in an event of a fatal 

crash, the odds†

 of a large truck occupant who 

was killed being unrestrained is much greater 
 National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

2

 Table 1 

 Large Truck Occupants Killed by Year, Occupant Type and Restraint Use in Fatal Crashes 

 Restraint Use

Year 

 Occupant 

 Type Not Used % Used % Unknown % Sub-Total 

 

Total 

1988 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 554 

 101 

 29 

 0 

73 

87 

97 

 0 

 72 

 6 

 0 

 0 

 9 

 5 

 0 

0 

 137 

 9 

 1 

 2 

 18 

 8 

 3 

100 

 763 

 116 

 30 

 2 

 

 911 

 

1989 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 479 

 100 

 20 

 0 

68 

79 

87 

 0 

 76 

 10 

 0 

 0 

11 

 8 

 0 

0 

 151 

 17 

 3 

 2 

 21 

 13 

 13 

100 

 706 

 127 

 23 

 2 

 

 858 

 

1990 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 405 

 84 

 16 

 0 

 69 

 83 

100 

 0 

 84 

 6 

 0 

 0 

14 

 5 

 0 

 0 

 97 

 12 

 0 

 1 

 17 

 12 

 0 

100 

 586 

 102 

 16 

 1 

 

 705 

 

1991 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 348 

 77 

 10 

 0 

63 

82 

91 

 0 

 88 

 6 

 0 

 0 

16 

 6 

 0 

 0 

 118 

 11 

 1 

 2 

 21 

 12 

 9 

100 

 554 

 94 

 11 

 2 

 

 661 

 

1992 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 289 

 47 

 12 

 0 

56 

81 

92 

 0 

 107 

 8 

 0 

 0 

21 

14 

 0 

 0 

 116 

 3 

 1 

 2 

 23 

 5 

 8 

100 

 512 

 58 

 13 

 2 

 

 585 

 

1993 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 319 

 57 

 13 

 0 

62 

75 

100 

 0 

 94 

 9 

 0 

 0 

18 

12 

 0 

 0 

 103 

 10 

 0 

 0 

 20 

 13 

 0 

 0 

 516 

 76 

 13 

 0 

 605 

1994 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 325 

 74 

 23 

 0 

59 

82 

88 

 0 

 105 

 5 

 0 

 0 

19 

 6 

 0 

 0 

 124 

 11 

 3 

 0 

 22 

 12 

 12 

 0 

 554 

 90 

 26 

 0 

 670 

1995 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 337 

 60 

 9 

 0 

 61 

 76 

 90 

 0 

 117 

 8 

 0 

 0 

21 

10 

 0 

 0 

 102 

 11 

 1 

 3 

 18 

 14 

 10 

100 

 556 

 79 

 10 

 3 

 648 

1996 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 331 

 51 

 13 

 0 

 61 

 82 

 81 

 0 

 116 

 4 

 1 

 0 

22 

 6 

 6 

 0 

 94 

 7 

 2 

 2 

 17 

 12 

 13 

100 

 541 

 62 

 16 

 2 

 621 

1997 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 370 

 59 

 21 

 1 

 59 

 80 

 95 

100 

 143 

 7 

 1 

 0 

23 

10 

 5 

 0 

 114 

 7 

 0 

 0 

 18 

 10 

 0 

 0 

 627 

 73 

 22 

 1 

 723 

1998 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 340 

 63 

 18 

 2 

 54 

 77 

 86 

100 

 155 

 6 

 0 

 0 

24 

 7 

 0 

 0 

 142 

 13 

 3 

 0 

 22 

 16 

 14 

 0 

 637 

 82 

 21 

 2 

 742 

1999 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 340 

 62 

 24 

 0 

 53 

 70 

 96 

 0 

 177 

 10 

 0 

 0 

27 

11 

 0 

 0 

 127 

 16 

 1 

 2 

 20 

 19 

 4 

100 

 644 

 88 

 25 

 2 

 759 

2000 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 372 

 52 

 19 

 4 

 57 

 72 

 83 

100 

 160 

 9 

 0 

 0 

24 

12 

 0 

 0 

 123 

 11 

 4 

 0 

 19 

 16 

 17 

 0 

 655 

 72 

 23 

 4 

 754 

2001 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 322 

 53 

 24 

 0 

 54 

 67 

 92 

 0 

 154 

 10 

 0 

 0 

25 

13 

 0 

 0 

 127 

 16 

 2 

 0 

 21 

 20 

 8 

 0 

 603 

 79 

 26 

 0 

 708 

2002 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 311 

 58 

 14 

 1 

 53 

 73 

 93 

100 

 157 

 13 

 0 

 0 

27 

16 

 0 

 0 

 120 

 9 

 1 

 0 

20 

11 

 7 

 0 

 588 

 80 

 15 

 1 

 684 

Total 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 5442 

 998 

 265 

 8 

 60 

 78 

 91 

 33 

 1805 

 117 

 2 

 0 

20 

 9 

 1 

 0 

 1795 

 163 

 23 

 16 

 20 

 13 

 8 

 67 

 9042 

 1278 

 290 

 24 

10634 

Source: NCSA FARS 1988-2002 
 National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

3

 Table 2 

 Large Truck Occupants Survived by Year, Occupant Type and Restraint Use in Fatal Crashes 

 Restraint Use

Year 

 Occupant 

 Type Not Used % Used % Unknown % Sub-Total 

 

Total 

1988 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 1791 

 384 

 107 

 0 

 41 

 59 

 96 

 0 

1927 

 175 

 2 

 0 

44 

27 

 4 

 0 

 645 

 86 

 2 

 0 

 15 

14 

 4 

 0 

 4363 

 645 

 111 

 0 

 5119 

1989 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 1613 

 321 

 86 

 0 

 38 

 61 

 94 

 0 

1951 

 164 

 4 

 0 

47 

25 

 4 

 0 

 612 

 95 

 2 

 0 

 15 

 14 

 2 

 0 

 4176 

 580 

 92 

 0 

 4848 

1990 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 1323 

 389 

 92 

 0 

 32 

 56 

 93 

 0 

2189 

 204 

 3 

 0 

53 

29 

 3 

 0 

 589 

 100 

 4 

 1 

 15 

 15 

 4 

100 

 4101 

 693 

 99 

 1 

 4894 

1991 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 1070 

 274 

 71 

 0 

 29 

 50 

 85 

 0 

 2170 

 204 

 4 

 0 

58 

37 

 5 

 0 

 485 

 70 

 9 

 0 

 13 

 13 

 10 

 0 

 3725 

 548 

 84 

 0 

 4357 

1992 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 838 

 222 

 79 

 0 

 24 

 47 

 91 

 0 

 2160 

 197 

 2 

 0 

63 

42 

 2 

 0 

 456 

 54 

 6 

 0 

 13 

 11 

 7 

 0 

 3454 

 473 

 87 

 0 

 4014 

1993 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 795 

 291 

 98 

 0 

 21 

 53 

 95 

 0 

 2477 

 203 

 1 

 0 

66 

37 

 1 

 0 

 467 

 60 

 4 

 0 

 13 

 10 

 4 

 0 

 3739 

 554 

 103 

 0 

 4396 

1994 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 847 

 253 

 95 

 0 

 21 

 44 

 93 

 0 

 2735 

 260 

 3 

 0 

68 

45 

 3 

 0 

 433 

 68 

 4 

 0 

 11 

 11 

 4 

 0 

 4015 

 581 

 102 

 0 

 4698 

1995 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 670 

 194 

 98 

 0 

 18 

 36 

 92 

 0 

 2745 

 283 

 2 

 0 

71 

53 

 2 

 0 

 428 

 62 

 6 

 0 

 11 

 11 

 6 

 0 

 3843 

 539 

 106 

 0 

 4488 

1996 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 733 

 235 

 98 

 0 

 18 

 38 

 92 

 0 

 3018 

 296 

 3 

 0 

73 

48 

 3 

 0 

 396 

 82 

 5 

 0 

 9 

 14 

 5 

 0 

 4147 

 613 

 106 

 0 

 4866 

1997 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 635 

 209 

 119 

 0 

 15 

 35 

 91 

 0 

 3155 

 326 

 4 

 0 

75 

54 

 3 

 0 

 418 

 69 

 8 

 0 

 10 

 11 

 6 

 0 

 4208 

 604 

 131 

 0 

 4943 

1998 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 597 

 265 

 114 

 2 

 14 

 40 

 97 

100 

 3221 

 326 

 3 

 0 

76 

49 

 2 

 0 

 415 

 71 

 1 

 0 

 10 

 11 

 1 

 0 

 4233 

 662 

 118 

 2 

 5015 

1999 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 572 

 191 

 136 

 0 

 14 

 33 

 95 

 0 

 3232 

 311 

 3 

 0 

77 

54 

 2 

 0 

 401 

 72 

 4 

 2 

 9 

 13 

 3 

100 

 4205 

 574 

 143 

 2 

 4924 

2000 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 542 

 196 

 135 

 1 

 13 

 32 

 95 

 50 

 3369 

 349 

 2 

 0 

79 

58 

 1 

 0 

 366 

 61 

 5 

 1 

 8 

 10 

 4 

 50 

 4277 

 606 

 142 

 2 

 5027 

2001 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 481 

 189 

 114 

 1 

 11 

 33 

100 

 3368 

 326 

 4 

 0 

81 

57 

 0 

 316 

 58 

 6 

 0 

 8 

 10 

 0 

 4165 

 573 

 124 

 1 

 4863 

2002 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 448 

 130 

 108 

 2 

 12 

 27 

 94 

100 

 3212 

 315 

 4 

 0 

82 

64 

 4 

 0 

 245 

 44 

 3 

 0 

 6 

 9 

 2 

 0 

 3905 

 489 

 115 

 2 

 4511 

Total 

 Driver 

 Other Passenger 

Sleeper Sec. Passenger 

 Unknown 

 12955 

 3743 

 1550 

 6 

 21 

 43 

 93 

 60 

40929 

 3938 

 44 

 0 

68 

45 

 3 

 0 

 6672 

 1052 

 69 

 4 

 11 

 12 

 4 

 40 

 60556 

 8734 

 1663 

 10 

70963 

Source: NCSA FARS 1988-2002 
 National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

4

 

 

Chart 1: Large Truck Drivers Killed 

by Restraint Use (1988-2002) in Fatal Crashes

0%

20%

40%

60%

80%

100%

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Year

Percent

Not Used Used Unknown

 

Chart 2: Large Truck Drivers Survived 

by Restraint Use (1988-2002) in Fatal Crashes

0%

20%

40%

60%

80%

100%

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Year

Percent

Not Used Used Unknown

 
 National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

5

 

Chart 3: Large Truck Passengers Killed 

by Restaint Use (1988-2002) in Fatal Crashes

0%

20%

40%

60%

80%

100%

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Year

Percent

Not Used Used Unknown

 

Chart 4: Large Truck Passengers Survived 

by Restaint Use (1988-2002) in Fatal Crashes

0%

20%

40%

60%

80%

100%

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Year

Percent

Not Used Used Unknown
 National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

6

than a large truck occupant who survived the 

fatal crash. In addition, the odds of the fatality 

being a large truck driver is almost twice that of 

the fatality being a large truck passenger 

(1/0.58=1.72). Examination of Table 1 and 2 

shows 12 percent of large truck drivers and 13 

percent of large truck passengers were killed in 

fatal crashes for the period 1988-2002 (not 

including occupants where the restraint use is 

unknown). On first glance, the similar fatality 

percentages between drivers and passengers and 

the results of the logistic analysis seem to be in 

conflict. However, the difference here can be 

explained by the difference in restraint use. The 

overall percentage of restraint use is 70 percent 

for drivers and 39 percent for passengers for the 

period 1988-2002 (not including occupants 

where the restraint use is unknown). Note that if 

the passengers in sleeper cabs are excluded, two 

similar odds ratio in logistic analysis are 

obtained as 0.64 and 9.48 in Table 3. 

† The “odds” is different from the probability 

(possibility). Odds = probability/(1-probability). 

For example, if two probabilities of an 

unrestrained and a restrained occupant to be 

killed are respectively 95% and 55% in fatal 

crashes (assuming the effectiveness of restraint 

systems in reducing fatalities is about 40% in 

fatal crashes [3]), then the odds ratio of an 

occupant to be killed for unrestrained vs. 

restrained is 15.5 (= [0.95/0.05] / [0.55/0.45]). 

References 

[1] National Highway Traffic Safety Administration. Traffic Safety Facts 2001. Washington, DC: 

 US Department of Transportation. 

[2] 2002 Annual Assessment. National Center for Statistics and Analysis, NHTSA, 

 http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2003/Assess02.pdf

[3] Evans, L. The Effectiveness of Safety Belts in Preventing Fatalities, Accident Analysis and 

 Prevention, 18: 229(1986). 

*Cejun Liu is a Program Analyst employed by Rainbow Technology Inc., a contractor working for the 

Mathematical Analysis Division, National Center for Statistics and Analysis, NHTSA. Very useful 

suggestions and comments from Chou-Lin Chen, Dennis Utter, Joseph Tessme at NCSA, Alan Block at 

NHTSA and Richard Gruberg at FMCSA, and technical assistance from Tom Bragan, Paul Lobo, Ellin 

Ramsey, Rajesh Subramanian and Umesh Shankar at NCSA are acknowledged.

 

For additional copies of this research note, please call 1-800-934-8517 or fax your request to (202) 366-3189. For 

questions regarding the data reported in this research, contact Cejun Liu [202-366-5354]. Internet users may access 

this research note and other general information on highway traffic safety at: http://wwwnrd.nhtsa.dot.gov/departments/nrd-30/ncsa/AvailInf.html

U.S. Department 

of Transportation

National Highway 

Traffic Safety 

Administration 

400 Seventh Street, S.W., NPO-120 

Washington, D.C. 20590