DOT HS 810 741 March 2007

An Analysis of Motor Vehicle 

Rollover Crashes and Injury 

Outcomes

This document is available to the public from the National Technical Information Service, Springfield, Virginia 22161

Published by

NHTSA’s National Center for Statistics and Analysis
This publication is distributed by the U.S. Department of Transportation, National Highway 

Traffic Safety Administration, in the interest of information exchange. The opinions, findings, 

and conclusions expressed in this publication are those of the author and not necessarily those of 

the Department of Transportation or the National Highway Traffic Safety Administration. The 

United States Government assumes no liability for its contents or use thereof. If trade or 

manufacturers’ names are mentioned, it is only because they are considered essential to the 

object of the publication and should not be construed as an endorsement. The United States 

Government does not endorse products or manufacturers. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

Technical Report Documentation Page 

1. Report No. 

DOT HS 810 741 

2. Government Accession No. 3. Recipients's Catalog No. 

5. Report Date 

March 2007 

4. Title and Subtitle 

An Analysis of Motor Vehicle Rollover Crashes and 

Injury Outcomes 6. Performing Organization Code 

NPO-121 

7. Author(s) 

Alexander Strashny 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)n code 

Mathematical Analysis Division, Office of Traffic Records and Analysis 

National Center for Statistics and Analysis 

National Highway Traffic Safety Administration 

U.S. Department of Transportation 

NPO-121, 400 Seventh Street SW. 

Washington, DC 20590 

11. Contract of Grant No. 

13. Type of Report and Period Covered 

NHTSA Technical Report 

12. Sponsoring Agency Name and Address 

Mathematical Analysis Division, Office of Traffic Records and Analysis 

National Center for Statistics and Analysis 

National Highway Traffic Safety Administration 

U.S. Department of Transportation 

NPO-121, 400 Seventh Street SW. 

Washington, DC 20590 

14. Sponsoring Agency Code 

15.Supplementary Notes 

16. Abstract 

Rollover crashes can have serious consequences. In 2004, 33% of passenger vehicle occupant fatalities were in vehicles that rolled 

over. This report analyzes data related to passenger vehicle rollovers, including rollover propensity and injury outcomes. The report 

uses the Fatality Analysis Reporting System and National Automotive Sampling System General Estimates System databases to 

tabulate data on passenger vehicles and their occupants by a variety of variables and performs logistic analysis of the data. 

Tabulations focus on years 1994, 2003, and 2004; logistic analysis pools data for years 2000 through 2004. We specifically analyze 

factors that (a) were associated with vehicle rollovers in single-vehicle crashes of passenger vehicles; and (b) were associated with 

ejection status and varying degrees of injury severity of occupants of passenger vehicles that rolled over in single-vehicle crashes. 

Among other things, we also analyze the relationship between various anthropomorphic characteristics, such as the Body Mass 

Index, and seat belt effectiveness for drivers of passenger vehicles that were in single-vehicle rollovers. This report may be useful 

to other researchers and may provide a starting point for further analysis of vehicle rollovers and injury outcomes. 

17. Key Words 

Rollover, single-vehicle, weight, body mass index, 

BMI, logistic, driver restraint use 

18. Distribution Statement 

Document is available to the public through the 

National Technical Information Service, 

Springfield, VA 22161 

19. Security Classif. (of this report) 

 Unclassified 

20. Security Classif. (of this page) 

 Unclassified 

21. No of Pages 

89 

22. Price 

Form DOT F1700.7 (8-72) Reproduction of completed page authorized 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

Table of Contents 

1. Executive Summary ------------------------------------------------------------------------------ 1 

2. Introduction---------------------------------------------------------------------------------------- 3 

3. Introductory Tables ------------------------------------------------------------------------------- 7 

4. Crash Avoidance ---------------------------------------------------------------------------------11 

5. Rollover Propensity------------------------------------------------------------------------------13 

Vehicle-Related Factors----------------------------------------------------------------------------13 

Driver-Related Factors -----------------------------------------------------------------------------15 

Other Factors ----------------------------------------------------------------------------------------28 

6. Injury Outcomes ---------------------------------------------------------------------------------39 

7. Fatalities Only ------------------------------------------------------------------------------------67 

Weight, Height, and Body Mass Index-----------------------------------------------------------67 

Fatalities by State -----------------------------------------------------------------------------------74 

8. Logistic Analysis---------------------------------------------------------------------------------78 

Rollover propensity---------------------------------------------------------------------------------78 

Injury Outcomes ------------------------------------------------------------------------------------81 

Discussion--------------------------------------------------------------------------------------------84 

Appendix: Interpretation of Logistic Tables-----------------------------------------------------84 

9. Conclusion ----------------------------------------------------------------------------------------86 

10. References -------------------------------------------------------------------------------------87 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

1 

List of Tables 

Table 1 Passenger vehicle crashes and rollovers (regardless of the number of vehicles in the 

crash), 1994-2004 ................................................................................................................... 7 

Table 2 Passenger vehicle occupants in vehicles that crashed and in vehicles that rolled over, 

1994-2004 ............................................................................................................................... 8 

Table 3 Passenger vehicle occupants by rollover status, injury severity, and ejection status, 1994-

2004......................................................................................................................................... 9 

Table 4 Passenger vehicles in rollovers by vehicle type, 1994, 2003, 2004................................. 11 

Table 5 Passenger vehicle drivers by rollover status and sex, 1994, 2003, 2004........................ 12 

Table 6 Passenger vehicle drivers in rollovers by age, 1994, 2004.............................................. 12 

Table 7 Vehicles in single-vehicle crashes ................................................................................... 13 

Table 8 Vehicles in single-vehicle crashes by vehicle type, vehicle age, and rollover status, 

1994, 2003, 2004................................................................................................................... 14 

Table 9 Vehicles in single-vehicle crashes by vehicle type, whether the crash was speed-related, 

and rollover status, 1997, 2003, 2004................................................................................... 15 

Table 10 Vehicles in single-vehicle crashes by vehicle type, driver restraint use, and rollover 

status, 1994, 2003, 2004 ....................................................................................................... 17 

Table 11 Vehicles in single-vehicle crashes by vehicle type, driver age, and rollover status, 

1994, 2003, 2004................................................................................................................... 18 

Table 12 Vehicles with two occupants in single-vehicle crashes by vehicle type, driver and 

passenger age, and rollover status, 1994, 2003, 2004........................................................... 19 

Table 13 Vehicles in single-vehicle crashes by vehicle type, driver sex, and rollover status, 

1994, 2003, 2004................................................................................................................... 21 

Table 14 Vehicles in single-vehicle crashes by vehicle type, alcohol involvement, and rollover 

status, 1994, 2003, 2004 ....................................................................................................... 23 

Table 15 Vehicles in single-vehicle crashes by vehicle type, maneuver prior to critical event, 

and rollover status, 1994, 2003, 2004................................................................................... 24 

Table 16 Vehicles in single-vehicle crashes by vehicle type, corrective action attempted, and 

rollover status, 1994, 2003, 2004.......................................................................................... 26 

Table 17 Vehicles in single-vehicle crashes by vehicle type, number of vehicle occupants, and 

rollover status, 1994, 2003, 2004.......................................................................................... 28 

Table 18 Vehicles in single-vehicle crashes by vehicle type, posted speed limit, and rollover 

status, 1994, 2003, 2004 ....................................................................................................... 29 

Table 19 Vehicles in single-vehicle crashes by vehicle type, road type, and rollover status, 1994, 

2003, 2004............................................................................................................................. 31 

Table 20 Vehicles in single-vehicle crashes by vehicle type, relation to junction, and rollover 

status, 1994, 2003, 2004 ....................................................................................................... 33 

Table 21 Vehicles in single-vehicle crashes ................................................................................. 35 

Table 22 Occupants of vehicles in single-vehicle rollovers by vehicle type and injury severity, 

1994, 2003, 2004................................................................................................................... 40 

Table 23 Occupants of vehicles in fatal single-vehicle rollovers by vehicle type and injury 

severity, 1994, 2003, 2004.................................................................................................... 41 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 24 Occupants of vehicles in single-vehicle rollovers by vehicle type and ejection status, 

1995, 2003, 2004................................................................................................................... 43 

Table 25 Occupants of vehicles in single-vehicle rollovers ......................................................... 44 

Table 26 Occupants of vehicles in single-vehicle rollovers by vehicle type, restraint use, and 

injury severity, 1994, 2003, 2004 ......................................................................................... 45 

Table 27 Occupants of vehicles in single-vehicle rollovers by vehicle type, restraint use, and 

ejection status, 1995, 2003, 2004.......................................................................................... 47 

Table 28 Occupant of vehicles in fatal single-vehicle rollovers by vehicle type, restraint use, and 

ejection status 1995, 2003, 2004........................................................................................... 49 

Table 29 Occupants of vehicles in single-vehicle rollovers by vehicle type, restraint and ejection 

status, and injury severity, 1995, 2003, 2004 ....................................................................... 50 

Table 30 Occupants of vehicles in single-vehicle rollovers by occupant age and injury severity, 

1994, 2003, 2004................................................................................................................... 55 

Table 31 Occupants 4 years old or younger of vehicles in single-vehicle rollovers by vehicle type 

and use of child safety seat, 1994, 2003, 2004 ..................................................................... 58 

Table 32 Occupants 4 years old and younger of vehicles in single-vehicle rollovers by vehicle 

type, use of child safety seats, and injury severity, 1994, 2003, 2004.................................. 59 

Table 33 Occupants of vehicles in single-vehicle rollovers by vehicle type, sex, and injury 

severity, 1994, 2003, 2004.................................................................................................... 62 

Table 34 Occupants of vehicles in single-vehicle rollovers by vehicle type, vehicle age, and 

injury severity, 1994, 2003, 2004 ......................................................................................... 64 

Table 35 Fatally injured drivers 20 years old or older in single-vehicle rollovers by sex, restraint 

use, and weight, 1998, 2003, 2004........................................................................................ 68 

Table 36 Fatally injured drivers 20 years old or older in single-vehicle rollovers by sex, restraint 

use, and height, 1998, 2003, 2004 ........................................................................................ 70 

Table 37 Fatally injured drivers 20 years old or older in single-vehicle rollovers by sex, restraint 

use, and Body Mass Index, 1998, 2003, 2004 ...................................................................... 72 

Table 38 Fatally injured occupants of passenger vehicles in single-vehicle rollovers, in all 

rollovers, and in all crashes by State (plus Puerto Rico), 1994, 2003, 2004 ........................ 74 

Table 39 Logistic analysis of vehicle rollover given involvement in a single-vehicle crash, 2000-

2004....................................................................................................................................... 79 

Table 40 Logistic analysis of occupant fatality given involvement in a single-vehicle rollover, 82 

Table 41 Relationship between probabilities and odds................................................................. 85 
NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

1. Executive Summary 

Objective. The primary purpose of this technical report is to provide descriptive characteristics 

on vehicles that have rolled over and on injuries to occupants of these vehicles. The data is 

provided by categories that are thought to be of interest to the customers of NHTSA’s National 

Center for Statistics and Analysis (NCSA), both internal and external. In particular, we focus on 

passenger vehicles that were in single-vehicle crashes and rollovers, and on injuries of occupants 

of passenger vehicles that were in single-vehicle rollovers. 

Methods. We provide simple analyses in the form of tables of counts and percentages, as well as 

more sophisticated multivariate analyses. Following the Introduction, five sections of the report 

provide tabulated data on vehicles that rolled over and on vehicle occupants in vehicles that 

rolled over. These tables give both counts and percentages. These are given for 2004, the latest 

year for which data is available; for 2003, the previous year; and for 1994, which is 10 years 

prior to 2004, or for the earliest year for which data is available, if it is later than 1994. 

Note that counts of vehicles and of nonfatally injured occupants are estimated. Calculation of 

standard errors and confidence intervals is discussed in the Introduction. On the other hand, 

counts of fatally injured occupants come from a census. 

We use logistic regression to model the propensity of vehicles in single-vehicle crashes to roll 

over, as well as the propensity of occupants in single-vehicle rollovers to be fatally injured. We 

also provide a brief discussion on the interpretation of the results of logistic regression. 

Results. Considering rollovers in all types of crashes, in 2004 2.7% of occupants who were in 

passenger vehicles that rolled over were fatally injured, compared to 0.2% of occupants killed 

who were in passenger vehicles that crashed but did not roll over. The same year, 33% of 

passenger vehicle occupant fatalities were in vehicles that rolled over. The rollover rates were 

higher for light trucks, as opposed to passenger cars; and for males and for younger drivers. 

Considering the probability that a vehicle rolled over given involvement in a single-vehicle 

crash, we find the following. We generally find that sport utility vehicles (SUVs) were more 

likely to have rolled over than pickups, which in turn were more likely to roll over than either 

vans or passenger cars. Vehicles that were more likely to roll over were older, were driven by 

younger, unbelted drivers, had more occupants, and were in speed-related crashes on roads with 

higher speed limits, in nonintersection areas. Alcohol involvement increased the probability of 

rollover. Vehicles that were more likely to roll over were passing as opposed to turning prior to 

the crash, and the drivers in such vehicles attempted to steer when they realized that the crash 

was imminent; the first harmful event in the crash was either the rollover itself or striking an 

embankment. 

In single-vehicle rollovers, SUVs had the highest rate of total ejection. Unrestrained occupants 

had more severe injuries and were totally ejected at a higher rate than restrained occupants. Older 

occupants had a higher fatality rate than younger ones; males had a higher fatality rate than 

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

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In single-vehicle rollovers, occupants who weighed more and who had a higher Body Mass 

Index (BMI) appeared to have received fewer benefits from seat belts. People who weighed less, 

were taller, and had a lower BMI tended to be overrepresented in fatalities as compared to the 

general population, regardless of seat belt use. Thus, while heavier individuals received fewer 

benefits from seat belts, they might also have been at a lower risk of fatality given involvement 

in a single-vehicle rollover regardless of seat belt use. 

In 2004, for the United States as a whole, 31,693 passenger vehicle occupants were fatally 

injured in crashes of all types, 10,553 were fatally injured in rollovers, and 8,565 were fatally 

injured in single-vehicle rollovers. This means that 33% of passenger vehicle occupant fatalities 

were in vehicles that rolled over. State-by-State, this percentage ranged from 10% for the District 

of Columbia to 67% for Montana. 

There were some factors that increased both the probability that a vehicle rolls over given that it 

is involved in a single-vehicle crash and the probability of an occupant fatality given that the 

occupant was in a vehicle that rolled over, while other factors increased the probability of one 

while decreasing the probability of the other. For example, if a vehicle was turning as opposed to 

going straight right before the single-vehicle crash occurred, that decreased the probability that 

the vehicle rolled over, and it also decreased the probability of occupant fatality if it did roll 

over. The same was true for the speed limit. A higher speed limit both increased the probability 

that a vehicle rolled over given that it was in a single-vehicle crash and it increased the 

probability of occupant fatality given that the occupant was in a vehicle that was in a singlevehicle rollover. 

On the other hand, light trucks had a higher probability of rolling over than passenger cars, but 

being an occupant in a light truck decreased the probability of a fatal injury given a singlevehicle rollover. Similarly, higher vehicle occupancy increased the probability of a vehicle 

rolling over given involvement in a single-vehicle crash, but at the same time it decreased the 

probability of occupant fatality given that the vehicle was involved in a single-vehicle rollover. 

Conclusion. This report provides a general overview of the different factors related to passenger 

vehicle rollovers. It might prompt more detailed research into specific areas that are deemed to 

be interesting. For example, one potentially interesting area for further research is the effect of 

seat belts on injury outcomes as a function of occupant characteristics, such as body weight. 

Other potentially interesting areas for research would include investigating further the use of the 

driver restraint use variable as a proxy for driver safety and studying the relationship between 

rollover propensity observed in actual crashes and certain vehicle characteristics, such as the 

Static Stability Factor (SSF). 

The report uses both the Fatality Analysis Reporting System (FARS) database and the National 

Automotive Sampling System General Estimates System (NASS GES) database. It could be 

extended with additional databases, such as the National Automotive Sampling System 

Crashworthiness Data System (NASS CDS). CDS contains variables relevant to rollovers that 

are not present in either FARS or GES, such as the number of quarter turns that a vehicle has 

rolled over. Previous studies of rollovers, such as Eigen (2005), have used this database. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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2. Introduction 

Purpose. The primary purpose of this technical report is to provide descriptive characteristics on 

vehicles that have rolled over and on injuries to occupants of these vehicles. The data is provided 

by categories that are thought to be of interest to the customers of NHTSA’s National Center for 

Statistics and Analysis, both internal and external. The report builds and expands upon Strashny 

(2005), which was written in response to a specific data request by NHTSA’s Office of Vehicle 

Safety Planning and Analysis. Certainly, for many of the topics discussed in this report, the 

discussion could be greatly expanded. The research as presented in the report was conducted to 

balance between breadth and depth of coverage of the various topics related to vehicle rollovers. 

By tabulating the data and by performing some regression analysis, this report explores the 

various factors associated with vehicle rollovers and with varying degrees of occupant injury in a 

rollover. Keep in mind that no retrospective statistical analysis can establish causality. Thus, 

when a strong association is found, the matter should be investigated further to determine if there 

was an actual causal relationship. The Haddon matrix is a useful framework for organizing the 

different aspects of crashes that is commonly used in the field of traffic safety (see Haddon, 

1980). In terms of the Haddon matrix, the report analyzes pre-event and event phases of the 

human, vehicle, and environmental factors. This report analyzes variable associations not only 

for 2004, the latest year for which data is available, but also for selected previous years. 

Data. The data is limited to passenger vehicles, which consist of passenger cars and light trucks. 

When the category of light trucks is divided into subcategories, these are vans, pickups, sport 

utility vehicles, and other light trucks. Note that the analysis is only on vehicles and their 

occupants, and excludes nonmotorists. For brevity, extraneous categories such as “unknown” and 

“other” have been removed from the tabulated counts. When percentages are shown, they are 

based on all the categories, including ones that have been removed. 

The initial few tables show annual data for years 1994 through 2004, the latest year for which 

data is available. Subsequent tables show annual data for 2004, 2003, the previous year, and for 

1994, which is 10 years prior to 2004, or for the earliest year for which data is available, if it is 

later than 1994. Regression analysis combines years 2000 through 2004. 

The data on occupants who were fatally injured are from the Fatality Analysis Reporting System 

database. According to Tessmer (2002), FARS “is a collection of files documenting all 

qualifying fatal crashes since 1975 that occurred within the 50 States, the District of Columbia, 

and Puerto Rico. To be included in this census of crashes, a crash had to involve a motor vehicle 

traveling on a trafficway customarily open to the public, and must result in the death of a person 

(occupant of a vehicle or a nonmotorist) within 30 days of the crash.” Note that following 

standard NCSA practice, we exclude Puerto Rico from all national-level counts and analyses; it 

is only included in the State-by-State analysis in the Fatalities Only section. FARS data for 2004 

is from the preliminary Annual Report File (ARF), while data from all the previous years is from 

the Final files. 

The data on all vehicle crashes, including fatal crashes, and on occupants who survived the 

crashes in which they were involved, come from the National Automotive Sampling System 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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General Estimates System database. According to NHTSA c (2004), “the GES obtains its data 

from a nationally representative probability sample selected from the estimated 6.2 million 

police-reported crashes which occur annually. These crashes include those that result in a fatality 

or injury and those involving major property damage.” 

When considering data at the vehicle level, we only use the GES database. When considering 

data at the occupant level, we take the data on fatally injured occupants from FARS, and data on 

all occupants who were not fatally injured from GES. 

The data on vehicle miles traveled is from the Federal Highway Administration, as revised by 

NHTSA; the data on registered passenger cars and light trucks is from R.L. Polk & Co.; the data 

on licenses drivers is from the Federal Highway Administration. 

For some variables, GES provides the variable together with its imputed version. Some analysts 

assume that the imputed versions of variables are better and automatically use them in their 

analysis. However, Shelton (1993), which discusses the imputation procedures used to create the 

imputed versions of variables in GES, states that these imputed versions of variables should only 

be used in univariate tables. Since almost all the tables in this report involve at least two 

variables, we do not use the imputed versions of variables. 

Note that GES is a probability sample that provides estimated rather than exact quantities. 

Estimation of the standard errors for these estimated quantities is discussed in NHTSA c (2004). 

In particular, let X be the estimate of a quantity obtained from GES. Then the estimated 

standard error of this quantity is ( ( ) ) 2exp a + b ln X . The values of the coefficients a and b vary 

by year and depend on whether the estimated quantity is at the crash level, vehicle level, or 

person level. The latest year for which NHTSA c (2004) provides values of a and b is 2003, 

though the values seem to have varied little from year to year. For 2003, for vehicle-level 

estimates, a = 4.2724 and b = 0.03553 ; for person-level estimates, a = 4.3572 and 

b = 0.03399 . For example, Table 1 lists the estimated number of passenger vehicles that have 

rolled over, by year. In 2003, the estimated number of passenger vehicles that rolled over was 

278,442. The standard error of this estimate is thus exp(4.2724 0.03553(ln278,442) ) 19,089 2 + = . 

From this, the 95% confidence interval for the number of passenger vehicles that rolled over in 

2003 is 278,442 ±1.96*19,089 = 241,029 to 315,855. From Table 2, in 2003, there were an 

estimated 389,800 occupants of passenger vehicles that had rolled over. Thus, the standard error 

of this estimate is 21,811; the 95% confidence interval for the number of occupants is 347,051 to 

432,549. 

NCSA maintains a number of databases that are representative probability samples. Some NCSA 

publications round counts obtained from such databases to the nearest thousand. For example, 

NHTSA e (2006) rounds estimated counts to the nearest thousand. This is done to emphasize the 

fact that these counts are estimates rather than true counts. However, such rounding might imply 

that the estimate is at least accurate to the nearest thousand, which may or may not be the case. 

For example, consider the sample calculations of standard errors presented above. In the 

previous two examples, the standard error is around 20,000, which means that the estimates in 

the examples are certainly not accurate to the nearest thousand. Instead, the range of the 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

5 

confidence interval is around 75,000 in the first example and around 85,000 in the second 

example. Thus, other NCSA publications do not round counts obtained from representative 

probability samples. They discuss the standard errors of the estimates and present the estimates 

themselves without rounding. See, for example, NHTSA a (1999). In this publication, consistent 

with the practice, we have discussed the calculation of standard errors, and we present all counts 

without rounding them to the nearest thousand. 

Another issue that makes rounding problematic is that when the counts are relatively small 

calculating percentages based on rounded and unrounded counts produces very different results. 

Thus, presenting rounded counts could be confusing or misleading. For example, consider Table 

12, which tabulates vehicles with two occupants in single-vehicle crashes by vehicle type, driver 

and passenger age, and rollover status, in the years 1994, 2003, and 2004. As with most other 

tables in this report, the first part of the table shows counts whereas the second part of the table 

shows percentages. Consider, for example, pickups with drivers who were 24 and younger and 

passengers who were 25 and older in 2004. There were an estimated 1,032 such vehicles in 

single-vehicle crashes, of which an estimated 508 rolled over. Thus, the probability of rollover 

for pickups with a younger driver and an older passenger in 2004 was an estimated 49% (= [508 

÷ 1,032]). However, if we performed rounding of the counts to the nearest thousand, we would 

state that there were an estimated 1,000 relevant pickups, of which an estimated 1,000 rolled 

over. This would make it appear that 100% of such pickups rolled over, which was certainly not 

the case. 

Particular caution should be taken when estimated counts are relatively small. The standard error 

of an estimated count as a percent of that count is a decreasing function of the estimated count. 

For example, consider 2003 person-level standard error estimates. If the estimated count was 

10,000, then its standard error was about 1,395, or 14% (= [1,395 ÷ 10,000]) of the estimated 

count. However, if the estimated count was 1,000, the standard error was 395, or 40% of the 

estimated count; if the estimated count was 100, then its estimated standard error was 160, or 

more than one and a half times of the estimated count itself. In other words, when estimated 

counts are relatively low, they, and the estimates of percentages that are based on them, are very 

inexact. For example, consider again Table 12. According to the table, of the sport utility 

vehicles with younger drivers and older passengers that were in single-vehicle crashes, an 

estimated 25% rolled over in 2003 but only an estimated 8% rolled over in 2004. Looking at the 

counts, we see that these percentages are based on an estimated 224 vehicle rollovers in 2003 

and 153 rollovers in 2004. As these estimated counts are so low, the estimates are inexact, which 

explains the great variability in the estimated percentages calculated using these estimated 

counts. 

Methods. The report presents both tabulated data as well as results of logistic regression 

analyses. When the analysis is at the vehicle level, all the data are from the GES database. When 

the analysis is at the occupant level, data on fatally injured occupants are from the FARS 

database and data on the occupants who were not fatally injured are from the GES database. 

Analyzing FARS rather than GES fatalities is standard practice since GES is a probability 

sample of all crashes while FARS is a census of fatal crashes. (For additional discussion, see 

NHTSA c (2004), p. 216.) 
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To perform logistic regressions, we use an SAS procedure called PROC SURVEYLOGISTIC. 

This procedure is new in version 9 of SAS. In performing logistic analysis, when the value of an 

explanatory variable for a particular observation is unknown, SAS drops the whole observation. 

To remedy this, we proceed as follows: if the variable is categorical, we follow the procedure 

used by Le Breton and Vervialle (2005) and use “Unknown” as its own category. This makes 

sense since the fact that the value of a particular variable was unknown may have been related to 

the event being modeled, such as rollover propensity or injury outcome. If the variable is 

interval, we replace unknown values with the average of that variable taken over all known 

values. This makes sense since a regression measures how the variability of explanatory 

variables around their averages is associated with the variability of the dependent variable. 

Setting an explanatory variable for a particular observation equal to its average means that, from 

the point of view of the regression model, the variable for that particular observation has no 

effect on the dependent variable. Replacing unknown interval scale variables in this way ensures 

that all of the available data is used, thus making the estimates more exact. Note however that we 

do not account for uncertainty due to these unknowns. Doing so would require performing 

multiple imputations for every interval scale variable that had an unknown value for at least one 

observation. Such a project is outside the scope of this report, requiring its own report. For an 

example of a report on the topic, see Subramanian (2002), which describes the multiple 

imputations procedure for the blood alcohol concentration variable in the FARS database. 

Report Structure. This report consists of the following sections, in order: Executive Summary, 

Introduction, Introductory Tables, Crash Avoidance, Rollover Propensity, Injury Outcomes, 

Fatalities Only, Logistic Analysis, and References. The Executive Summary section, at the front 

of this report, is a brief summary of all of the report’s findings. The Introduction, this section, 

familiarizes the reader with the purpose of this report, the databases used, and the methodology 

employed. The Introductory Tables section gives tables with counts of passenger vehicles that 

have rolled over, of occupants of such vehicles, and of injury outcomes of such vehicle 

occupants. The Crash Avoidance section gives rates for passenger vehicles that had rolled over, 

as well as for drivers of such vehicles; the Rollover Propensity section gives tables that show 

rollover rates in single-vehicle crashes. The section is subdivided into the Vehicle-Related 

Factors subsection, the Driver-Related Factors subsection, and the Other Factors subsection. The 

Injury Outcomes section shows injury outcomes and total ejection statuses of occupants who 

were in passenger vehicles that rolled over in single-vehicle crashes; the Fatalities Only section 

has tables for data on fatally injured occupants rather than all occupants in crashes. The reason 

that nonfatally injured occupants are not included is that the variables tabulated in this section 

were not present in the GES database. The section has two sub-sections. The first subsection 

tabulates the weight, height, and Body Mass Index of fatally injured drivers in single-vehicle 

rollovers. The second subsection tabulates rollover fatalities by State; the Logistic Analysis 

section describes the results of multivariate analysis of the data; the Rollover Propensity 

subsection models the propensity of vehicles to roll over given involvement in a single-vehicle 

crash. The Injury Outcomes subsection models the odds of occupant fatality given involvement 

in a single-vehicle rollover. The Discussion subsection compares the results of the two logistic 

models. Finally, the Appendix subsection briefly discusses the interpretation of logistic 

regression estimates; the Conclusion section provides concluding remarks; the References 

section lists references and acknowledgements. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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3. Introductory Tables 

This section contains some introductory tables to familiarize the reader with the data and with 

the general extent of the rollover issue as it existed from 1994 to 2004. The tables show annual 

data for years 1994 through 2004, the latest year for which data are available. Vehicle-level data 

in Table 1 are from the GES database, whereas occupant-level data in Tables 2 and 3 are from a 

combination of the FARS and the GES databases. Specifically, the data on occupants who were 

fatally injured is from the FARS database, while the data on occupants who were not fatally 

injured is from the GES database. 

Vehicles. In 2004, an estimated 275,637 passenger vehicles rolled over, as compared to 237,504 

vehicles in 1994, an increase of 16% (= [275,637 - 237,504] ÷ 237,504). As there were an 

estimated 11,728,411 vehicles in crashes in 2004, 2.4% (= [275,637 ÷ 11,728,411]) of the 

vehicles in crashes rolled over, as shown in Table 1. Although the results could be due to 

sampling error, it appears that both the number of rollovers and the rollover rate per total 

vehicles in crashes have increased over the years. 

In 2004, passenger vehicles traveled 2,719 billion vehicle miles (Vehicle Miles Traveled - 

VMT). This means that there were an estimated 10.1 vehicles that have rolled over per 100 

million VMT. This rollover rate has decreased by 7.3% (= [10.9 – 10.1] ÷ 10.9) since 1994. 

Since 1994, 2004 had the lowest rollover rate per VMT. There were 223,214,000 registered 

passenger vehicles in 2004, making the rollover rate an estimated 123 vehicles that have rolled 

over per 100,000 registered vehicles. This rate, again, was the lowest since 1994. Finally, there 

were a total of 198,889,000 licensed drivers, making an estimated 139 passenger vehicles that 

have rolled over per 100,000 licensed drivers in 2004. Unlike the rollover rates per VMT and 

100,000 registered vehicles, the licensed driver roll rate was slightly higher than that in 1994. 

Table 1 

Passenger vehicle crashes and rollovers (regardless of the number of vehicles in the crash), 

1994-2004 

Year Rolled 

over 

Total 

vehicles in 

crashes 

% 

Rolled 

over 

VMT 

(billions) 

Rolled 

over 

per 

100 

million 

VMT 

Registered 

vehicles 

(thousands) 

Rolled 

over per 

100,000 

registered 

vehicles 

Licensed 

drivers 

(thousands) 

Rolled 

over 

per 

100,000 

licensed 

drivers 

1994 237,504 11,684,680 2.0 2,171 10.9 181,483 131 175,403 135 

1995 243,431 12,171,372 2.0 2,228 10.9 185,763 131 176,628 138 

1996 268,901 12,273,601 2.2 2,286 11.8 190,052 141 179,539 150 

1997 259,158 12,008,921 2.2 2,353 11.0 191,960 135 182,709 142 

1998 252,098 11,547,388 2.2 2,418 10.4 195,749 129 184,861 136 

1999 275,207 11,371,434 2.4 2,470 11.1 200,013 138 187,170 147 

2000 295,369 12,198,795 2.4 2,523 11.7 203,913 145 190,625 155 

2001 294,729 12,020,364 2.5 2,572 11.5 207,720 142 191,276 154 

2002 273,022 11,990,929 2.3 2,625 10.4 211,993 129 194,602 140 

2003 278,442 11,987,190 2.3 2,656 10.5 216,730 128 196,166 142 

2004 275,637 11,728,411 2.4 2,719 10.1 223,214 123 198,889 139 

Source: NHTSA, NCSA, GES, R.L. Polk, 1994-2004. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

8 

Occupants. Now, consider the same information at the occupant level rather than the vehicle 

level. In 2004, there were an estimated 393,545 occupants in passenger vehicles that rolled over, 

as compared to 358,933 occupants in 1994, a 9.6% increase, as shown in Table 2. Since there 

were an estimated 14,099,883 occupants in passenger vehicles that crashed, 2.8% of occupants in 

crashes were in vehicles that rolled over. There were an estimated 14.5 occupants in vehicles that 

rolled over per 100 million VMT, 176 per 100,000 registered vehicles, and 198 per 100,000 

licensed drivers. In 2004, the rates per VMT and per registered vehicles were the lowest that they 

have been since 1994. The last column of Table 2 uses information presented in Table 1 to 

calculate the average number of occupants per rollover. Thus, for example, in 2004, there were 

an estimated 1.43 (= [393,545 ÷ 275,637]) occupants per rollover. 

Table 2 

Passenger vehicle occupants in vehicles that crashed and in vehicles that rolled over, 1994-

2004 

Year 

Occupants 

in vehicles 

that rolled 

over 

Occupants 

in all 

vehicles 

that 

crashed 

% in 

vehicles 

that 

rolled 

over 

VMT 

(billions) 

In 

vehicles 

that 

rolled 

over per 

100 

million 

VMT 

Registered 

vehicles 

(thousands) 

In 

vehicles 

that 

rolled 

over per 

100,000 

registered 

vehicles 

Licensed 

drivers 

(thousands) 

In 

vehicles 

that 

rolled 

over per 

100,000 

licensed 

drivers 

Occupants 

per 

rollover 

1994 358,933 15,578,690 2.3 2,171 16.5 181,483 198 175,403 205 1.51 

1995 363,025 16,362,004 2.2 2,228 16.3 185,763 195 176,628 206 1.49 

1996 394,434 16,496,950 2.4 2,286 17.3 190,052 208 179,539 220 1.47 

1997 375,439 16,049,187 2.3 2,353 16 191,960 196 182,709 205 1.45 

1998 354,473 15,386,637 2.3 2,418 14.7 195,749 181 184,861 192 1.41 

1999 392,307 14,826,683 2.6 2,470 15.9 200,013 196 187,170 210 1.43 

2000 415,418 14,789,760 2.8 2,523 16.5 203,913 204 190,625 218 1.41 

2001 410,494 14,477,919 2.8 2,572 16 207,720 198 191,276 215 1.39 

2002 390,958 14,427,318 2.7 2,625 14.9 211,993 184 194,602 201 1.43 

2003 389,800 14,394,424 2.7 2,656 14.7 216,730 180 196,166 199 1.40 

2004 393,545 14,099,883 2.8 2,719 14.5 223,214 176 198,889 198 1.43 

Source: NHTSA, NCSA, FARS, GES, R.L. Polk., 1994-2004. 

Injury Outcomes. As Table 3 shows, in 2004, of the estimated 393,545 occupants who were in 

passenger vehicles that rolled over, 10,553 occupants were fatally injured. Thus, the probability 

of death given involvement in a rollover was an estimated 2.7% (= [10,553 ÷ 393,545]). The 

number of occupants killed in passenger vehicles that rolled over increased from an estimated 

8,981 in 1994 by 17.5% (= [10,553 - 8,981] ÷ 8,981). By comparison, when a passenger vehicle 

did not roll over in a crash, the probability of fatality was an estimated 0.2%. The number of 

those killed in vehicles that crashed but did not roll over has actually decreased by 3.6% from 

1994 to 2004. 

In 2004, an estimated 15,312 occupants in vehicles that rolled over were totally ejected from 

their vehicles. This constitutes 3.9% (= [15,312 ÷ 393,545]) of all the occupants who were in 

vehicles that rolled over were completely ejected from the vehicles. By contrast, of the occupants 

who were in vehicles that crashed but did not roll over, only an estimated 6,207 occupants were 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

9 

totally ejected. There were thus 2.5 times (= [15,312 ÷ 6,207]) as many total ejections in vehicles 

that rolled over as there were in vehicles that crashed but did not roll over. 

Table 3 

Passenger vehicle occupants 

by rollover status, injury severity, and ejection status, 1994-2004 

Rolled Over (#) 

Year 

Fatal Incapacitating 

Injury Other Injury No Injury Total** Total Ejection 

1994 8,981 51,457 147,170 151,324 358,933 * 

1995 9,537 46,690 165,680 141,118 363,025 12,431 

1996 9,624 51,553 178,288 154,969 394,434 12,626 

1997 9,527 46,741 170,910 148,261 375,439 12,332 

1998 9,773 47,572 165,369 131,759 354,473 12,729 

1999 10,140 54,081 182,049 146,037 392,307 17,922 

2000 9,959 62,997 190,781 151,681 415,418 20,994 

2001 10,157 54,280 192,638 153,419 410,494 17,989 

2002 10,729 50,913 181,700 147,616 390,958 16,246 

2003 10,442 47,734 189,402 142,222 389,800 16,457 

2004 10,553 47,284 184,408 151,301 393,545 15,312 

Source: NHTSA, NCSA, FARS, GES, R.L. Polk., 1994-2004. 

* Total ejection data are available starting in 1995. 

** Total includes unknowns. 

No Rollover (#) 

Year 

Fatal Incapacitating 

Injury Other Injury No Injury Total Total Ejection 

1994 21,920 307,798 2,846,108 12,043,931 15,219,758 * 

1995 22,454 320,857 3,248,940 12,406,727 15,998,978 8,285 

1996 22,813 310,358 3,084,905 12,684,439 16,102,516 7,024 

1997 22,921 312,025 3,042,019 12,296,782 15,673,748 6,961 

1998 22,126 291,464 3,018,988 11,699,586 15,032,164 7,081 

1999 21,987 286,760 2,827,114 11,298,515 14,434,376 10,323 

2000 22,266 270,973 2,728,433 11,352,670 14,374,342 9,849 

2001 21,886 252,468 2,639,305 11,153,766 14,067,425 6,785 

2002 22,114 248,073 2,594,276 11,171,898 14,036,361 7,321 

2003 21,829 214,664 2,594,172 11,173,959 14,004,625 7,189 

2004 21,140 206,156 2,478,897 11,000,145 13,706,338 6,207 

Source: NHTSA, NCSA, FARS, GES, R.L. Polk., 1994-2004. 

* Total ejection data are available starting in 1995. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

10 

Rolled Over (%) 

Year 

Fatal Incapacitating 

Injury Other Injury No Injury Total Ejection 

1994 2.5 14.3 41.0 42.2 * 

1995 2.6 12.9 45.6 38.9 3.4 

1996 2.4 13.1 45.2 39.3 3.2 

1997 2.5 12.4 45.5 39.5 3.3 

1998 2.8 13.4 46.7 37.2 3.6 

1999 2.6 13.8 46.4 37.2 4.6 

2000 2.4 15.2 45.9 36.5 5.1 

2001 2.5 13.2 46.9 37.4 4.4 

2002 2.7 13.0 46.5 37.8 4.2 

2003 2.7 12.2 48.6 36.5 4.2 

2004 2.7 12.0 46.9 38.4 3.9 

Source: NHTSA, NCSA, FARS, GES, R.L. Polk., 1994-2004. 

* Total ejection data are available starting in 1995. 

No Rollover (%) 

Year 

Fatal Incapacitating 

Injury Other Injury No Injury Total Ejection 

1994 0.1 2.0 18.7 79.1 * 

1995 0.1 2.0 20.3 77.5 0.1 

1996 0.1 1.9 19.2 78.8 0.0 

1997 0.1 2.0 19.4 78.5 0.0 

1998 0.1 1.9 20.1 77.8 0.0 

1999 0.2 2.0 19.6 78.3 0.1 

2000 0.2 1.9 19.0 79.0 0.1 

2001 0.2 1.8 18.8 79.3 0.0 

2002 0.2 1.8 18.5 79.6 0.1 

2003 0.2 1.5 18.5 79.8 0.1 

2004 0.2 1.5 18.1 80.3 0.0 

Source: NHTSA, NCSA, FARS, GES, R.L. Polk., 1994-2004. 

* Total ejection data are available starting in 1995. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

11 

4. Crash Avoidance 

The tables in this section show annual vehicle-level data on vehicles that rolled over in 2004, the 

latest year for which data is available, in 2003 (except Table 6), the previous year, and in 1994, 

which is 10 years prior to 2004. As discussed previously in the Introductory Tables section, the 

vehicle-level data come from the GES database, not from the FARS database. 

Vehicles by Type. Table 4 gives counts and rates of vehicles that have rolled over by two 

vehicle types: passenger car and light truck. Light trucks include vans, pickups, sports utility 

vehicles, and other light trucks. In 2004, of the two types, light trucks had the higher number of 

rollovers at an estimated 150,802 rollovers – 59% of the passenger vehicles that rolled over were 

light trucks. They also had the higher increase in rollovers from 1994 to 2004: 57%, as compared 

to a decrease of 15% for passenger cars. In 2004, light trucks also had the higher rate of rollovers 

per 100 million VMT at an estimated 13.8 as compared to 6.5 for passenger cars. The rate for 

light trucks was 2.1 times as much as it was for passenger cars. In 1994, the rate for light trucks 

was 1.6 times of what it was for passenger cars. This increase in the rates ratio is primarily due to 

a decrease in the rate for passenger cars, as the rate for light trucks has remained about the same. 

Table 4 

Passenger vehicles in rollovers 

by vehicle type, 1994, 2003, 2004 

Vehicles that have rolled over VMT (billions) Rollovers per 100 million VMT 

Passenger car Light Truck Year 

# % # % 

Passenger car Light Truck Passenger car Light Truck 

1994 124,187 56 96,082 44 1,459 712 8.5 13.5 

2003 110,265 42 149,651 58 1,612 1,044 6.8 14.3 

2004 105,994 41 150,802 59 1,624 1,096 6.5 13.8 

Source: NHTSA, NCSA, GES, R.L. Polk., 1994, 2003, 2004. 

Drivers by Sex. As seen in Table 5, in 2004, an estimated 251,804 passenger vehicle drivers 

with known sex were in vehicles that rolled over. Of these, an estimated 159,808, 63% of the 

total, were male, and 91,996, or 37%, were female. In 2004, of the drivers of passenger vehicles 

that crashed but did not roll over, an estimated 5,406,097, or only 56%, were male. There were 

99,571,000 licensed male drivers, which makes the rate in 2004 an estimated 160 male drivers (= 

[100 * 159,808 ÷ 99,571]) in rollovers per 100,000 licensed male drivers. By contrast, there were 

only an estimated 93 female drivers in vehicles that rolled over per 100,000 licensed female 

drivers. Note that to obtain these rates, we are dividing the number of passenger vehicle drivers 

in rollovers by the number of licensed drivers of all vehicle types. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

12 

Table 5 

Passenger vehicle drivers 

by rollover status and sex, 1994, 2003, 2004 

Drivers in rollovers Drivers in non-rollovers 

Licensed 

drivers 

(thousands) 

Drivers in 

rollovers per 

100,000 

licensed 

drivers 

Male Female Male Female 

Year # % # % # % # % Male Female Male Female 

1994 143,295 67 71,388 33 5,921,537 59 4,193,046 41 89,194 86,210 161 83 

2003 162,225 64 91,435 36 5,514,335 56 4,288,424 44 98,228 97,937 165 93 

2004 159,808 63 91,996 37 5,406,097 56 4,252,755 44 99,571 99,318 160 93 

Source: NHTSA, NCSA, GES, R.L. Polk., 1994, 2003, 2004. 

Drivers by Age. Considering drivers who were in vehicles that rolled over by age groups, of the 

age groups considered in Table 6, the group with the highest number of drivers in 2004 is the 16- 

to 20-year-old group, with an estimated 67,366 drivers. Let us consider the rate of drivers of 

passenger vehicles that rolled over per 100,000 licensed drivers by age group. For example, in 

2004, there were 12,485,000 licensed drivers between the ages of 16 and 20, making the rate for 

this group an estimated 540. The rate decreased with increasing age. Thus, for drivers 75 or 

older, the rate in 2004 was only 22, about 25 times less. 

Table 6 

Passenger vehicle drivers in rollovers 

by age, 1994, 2004 

1994 2004 

Age Drivers in 

rollovers 

Licensed 

drivers 

(thousands) 

Drivers in rollovers 

per 100,000 

licensed drivers 

Drivers in 

rollovers 

Licensed 

drivers 

(thousands) 

Drivers in rollovers 

per 100,000 

licensed drivers 

16 to 20 66,457 11,729 567 67,366 12,485 540 

21 to 24 29,065 13,143 221 38,367 13,722 280 

25 to 34 52,412 38,991 134 53,809 36,065 149 

35 to 44 33,392 38,958 86 41,559 40,758 102 

45 to 54 16,843 28,713 59 25,395 39,192 65 

55 to 64 6,821 19,020 36 13,951 27,665 50 

65 to 74 4,293 15,755 27 4,898 16,365 30 

75 and older 2,105 9,037 23 2,806 12,611 22 

Source: NHTSA, NCSA, GES, R.L. Polk., 1994, 2004. 

Discussion. The crash avoidance tables show that, in the years under consideration, light trucks 

were more likely to roll over than passenger cars. They also show that male drivers were more 
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13 

likely to be in vehicles that rolled over than female drivers, and that drivers who were younger 

were more likely to be involved than drivers who were older. 

5. Rollover Propensity 

This section considers passenger vehicles that have rolled over given that they were in a singlevehicle crash. Single-vehicle crashes are crashes that involve only a single vehicle in transport, 

not counting legally parked vehicles. The reason that we only consider single-vehicle crashes is 

that we wish to study the propensity of each vehicle itself to roll over. Single-vehicle crashes are 

often considered in studies of rollover propensity. See, for example, Dalrymple (2003). Also, a 

vehicle characteristic used by NHTSA, called the Static Stability Factor (SSF), has been found to 

highly correlate with the probability that a vehicle rolls over given that it is involved in a tripped 

single-vehicle crash (Walz, 2005; Committee for the Study of a Motor Vehicle Rollover Rating 

System, 2002). Thus, focusing on single-vehicle crashes makes the data more relevant to studies 

related to SSF. 

The tables in this section show annual data for 2004, the latest year for which data is available, 

2003, the previous year, and 1994, which is 10 years prior to 2004. The data in all the tables 

come from the GES database. Note that the percentage tables in this section show the proportion 

of vehicles that have rolled over as a percent of all vehicles that were in single-vehicle crashes. 

Thus, the percentages in the tables do not, and are not intended to, add up to 100%. 

Vehicle-Related Factors 

Vehicles by Type. As Table 7 shows, in 2004, an estimated 980,463 passenger cars were in 

single-vehicle crashes, of which an estimated 94,836 passenger cars rolled over. This means that 

in 2004, the probability of rollover for passenger cars given involvement in such a crash was 

10% (= [94,836 ÷ 980,463]). In 2004, the highest probability of rollover given involvement in a 

single-vehicle crash was for sport utility vehicles at 23%. This probability was 2.3 times (= [23% 

÷ 10%]) as great as for passenger cars. Likewise, the probability of rollover for pickups was 1.7 

times higher than the probability of rollover for passenger cars. From 1994 to 2004, the 

probability of rollover for passenger cars had remained about the same at 10%, but had decreased 

slightly for light trucks. For example, for pickups, it went from 19% in 1994 to 17% in 2004. 

Note that, to improve readability, the table omits years 1995 through 2002. 

Table 7 

Vehicles in single-vehicle crashes 

by vehicle type and rollover status, 1994, 2003, 2004 

Vehicles Type/Rollover Status (#) 1994 2003 2004 

Rolled Over 114,116 97,962 94,836 Passenger car Total 1,174,709 1,036,538 980,463

Rolled Over 9,942 11,408 11,116 Van Total 100,986 129,757 118,678

Rolled Over 52,123 49,078 48,933 Pickup Total 276,363 291,675 292,625

Rolled Over 18,154 57,686 56,962 Sport Utility Vehicle Total 73,469 227,770 246,221

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Vehicles Type/Rollover Status (%) 1994 2003 2004 

Passenger car Rolled Over 10 9 10

Van Rolled Over 10 9 9

Pickup Rolled Over 19 17 17

Sport Utility Vehicle Rolled Over 25 25 23

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicles by Age. Since vehicle age is not given in the databases, we follow Morgan (1999) and 

define vehicle age as the difference between the year in which the crash occurred and the model 

year of the vehicle. Note that this does not give the exact vehicle age as some vehicles may be 

sold as early as the year prior to their model year. This fact can result in a negative vehicle age, 

as measured by this calculation. 

According to Table 8, in 2004, an estimated 27,905 passenger cars that were less than 5 years old 

rolled over when they were in single-vehicle crashes, compared to an estimated 66,687 that were 

5 years old or older. For all four vehicle types, the probability of rollover for the older vehicles 

was slightly higher than for the newer vehicles. For example, the probability for older sport 

utility vehicles was 26%, compared to 20% for newer sport utility vehicles. 

Table 8 

Vehicles in single-vehicle crashes 

by vehicle type, vehicle age, and rollover status, 1994, 2003, 2004 

Vehicle Type/Vehicle Age/Rollover Status (#) 1994 2003 2004 

Rolled Over 37,539 28,271 27,905 Less than 5 Years 

Total 422,226 342,638 311,480

Rolled Over 76,577 69,565 66,687 Passenger car 

5 Years or More 

Total 752,483 669,174 646,712

Rolled Over 3,885 3,150 3,338 Less than 5 Years 

Total 47,472 41,265 39,806

Rolled Over 6,057 8,258 7,778

Van 

5 Years or More 

Total 53,514 83,796 75,671

Rolled Over 16,855 18,479 19,037 Less than 5 Years 

Total 104,010 117,073 114,646

Rolled Over 35,268 30,599 29,843 Pickup 

5 Years or More 

Total 172,353 169,229 171,696

Rolled Over 6,681 21,960 22,356 Less than 5 Years 

Total 30,621 102,371 110,789

Rolled Over 11,473 35,727 34,606 Sport Utility Vehicle 

5 Years or More 

Total 42,848 120,795 131,799

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

15 

Vehicle Type/Vehicle Age/Rollover Status (%) 1994 2003 2004 

Less than 5 Years Rolled Over 9 8 9

Passenger car 5 Years or More Rolled Over 10 10 10

Less than 5 Years Rolled Over 8 8 8

Van 

5 Years or More Rolled Over 11 10 10

Less than 5 Years Rolled Over 16 16 17

Pickup 5 Years or More Rolled Over 20 18 17

Less than 5 Years Rolled Over 22 21 20

Sport Utility Vehicle 5 Years or More Rolled Over 27 30 26

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Driver-Related Factors 

Speed-Related. If speed is judged by the police to be a contributing factor to the cause of the 

crash, the crash is called speed-related. We use the GES variable SPEEDREL and the 

classification in Lindsey (2006) to determine if the crash was speed-related. As Table 9 shows, in 

2004, an estimated 249,151 single-vehicle car crashes were speed-related. In these crashes, an 

estimated 40,744 passenger cars rolled over. This made the probability of passenger car rollover 

in speed-related crashes 16%, compared to 8% for crashes that were not speed-related. Passenger 

cars were 2 times (= [16 ÷ 8]) as likely to roll over in speed-related crashes as in non-speedrelated crashes. This probability ratio was highest for vans, at 3.1 (= [22 ÷ 7]). 

Table 9 

Vehicles in single-vehicle crashes 

by vehicle type, whether the crash was speed-related, and rollover status, 1997, 2003, 2004 

Vehicle Type/Speed-Related Crash/Rollover Status (#) 1997 2003 2004 

Rolled Over 51,973 45,075 40,744 Speed-related 

Total 257,623 259,045 249,151

Rolled Over 52,567 48,992 50,611 Passenger car 

Not speed-related 

Total 730,642 704,305 667,204

Rolled Over 4,691 4,271 3,702 Speed-related 

Total 15,649 20,579 17,161

Rolled Over 6,269 6,896 6,852

Van 

Not speed-related 

Total 79,676 98,276 92,882

(Continued on Next Page) 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

16 

Vehicle Type/Speed-Related Crash/Rollover Status (#) 1997 2003 2004 

Rolled Over 23,154 21,498 21,888 Speed-related 

Total 72,840 70,814 71,663

Rolled Over 26,215 26,055 25,851 Pickup 

Not speed-related 

Total 185,670 205,037 205,493

Rolled Over 6,457 25,510 23,375 Speed-related 

Total 18,834 66,115 66,745

Rolled Over 15,224 30,833 31,409 Sport Utility Vehicle 

Not speed-related 

Total 61,692 149,177 165,935

Source: NHTSA, NCSA, GES, 1997, 2003,2004 

Note: Speed-related data available starting in 1997 

Vehicle Type/Speed-Related Crash/Rollover Status (%) 1997 2003 2004 

Speed-related Rolled Over 20 17 16

Passenger car 

Not speed-related Rolled Over 7 7 8

Speed-related Rolled Over 30 21 22

Van 

Not speed-related Rolled Over 8 7 7

Speed-related Rolled Over 32 30 31

Pickup 

Not speed-related Rolled Over 14 13 13

Speed-related Rolled Over 34 39 35

Sport Utility Vehicle 

Not speed-related Rolled Over 25 21 19

Source: NHTSA, NCSA, GES, 1997, 2003,2004 

Note: Speed-related data available starting in 1997 

Driver Restraint Use. Restraint use is the police-reported use of available vehicle restraints. It 

may reflect self-reporting by occupants of vehicles that crashed, and might thus be a biased 

estimate of actual restraint use. 

According to Table 10, across all vehicle types and years, vehicles of restrained drivers that were 

involved in a single-vehicle crash were less likely to roll over than vehicles of unrestrained 

drivers. One possible interpretation of this data is that the drivers who chose to use restraints also 

chose to drive safer. These safer drivers could have been less likely to have been in vehicles that 

crashed, and also could have been less likely to have been in a vehicle that rolled over if it was in 

a crash. Another possible interpretation of the data is that given that a vehicle is involved in a 

crash, restrained drivers may be in a better position to mitigate rollovers by retaining better 

control over their vehicles. 

In the 2004 single-vehicle car crashes in passenger cars that had a driver, an estimated 766,349 

drivers used restraints while an estimated 51,861 did not. In those cases when the driver used 

restraints, there were 76,642 passenger car rollovers. The probability of passenger car rollover 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

17 

with a restrained driver was thus 10% (= [76,642 ÷ 766,349]), compared to 17% when the driver 

was unrestrained. Note that in sport utility vehicles with unrestrained drivers, the rollover 

probability was 40%. 

Table 10 

Vehicles in single-vehicle crashes 

by vehicle type, driver restraint use, and rollover status, 1994, 2003, 2004 

Vehicle Type/Restraint Use/Rollover Status (#) 1994 2003 2004 

Rolled Over 78,839 71,186 76,642 Restrained 

Total 806,536 789,117 766,349

Rolled Over 21,178 14,263 8,855 Passenger car 

Unrestrained 

Total 137,251 68,248 51,861

Rolled Over 7,502 9,177 9,267 Restrained 

Total 71,593 95,490 91,444

Rolled Over 1,264 1,316 916

Van 

Unrestrained 

Total 8,015 6,618 3,644

Rolled Over 30,723 35,623 38,083 Restrained 

Total 173,977 221,790 230,913

Rolled Over 13,973 8,662 6,357 Pickup 

Unrestrained 

Total 54,306 27,113 21,436

Rolled Over 12,145 46,297 47,636 Restrained 

Total 50,327 181,396 199,896

Rolled Over 3,914 6,937 6,262 Sport Utility Vehicle 

Unrestrained 

Total 8,880 14,983 15,645

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Restraint Use/Rollover Status (%) 1994 2003 2004 

Restrained Rolled Over 10 9 10

Passenger car 

Unrestrained Rolled Over 15 21 17

Restrained Rolled Over 10 10 10

Van 

Unrestrained Rolled Over 16 20 25

Restrained Rolled Over 18 16 16

Pickup 

Unrestrained Rolled Over 26 32 30

Restrained Rolled Over 24 26 24

Sport Utility Vehicle 

Unrestrained Rolled Over 44 46 40

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Younger Drivers. Following Kindelberger and Eigen (2003), we define younger drivers as those 

drivers who were 24 or younger at the time of the crash. As seen in Table 11, of the passenger 

car drivers in cars that were in single-vehicle car crashes in 2004, an estimated 372,920 were 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

18 

between 16 and 24, while an estimated 533,328 were 25 or older. Of these older passenger car 

drivers, 41,937, or 8%, were in vehicles that rolled over. On the other hand, 13% of the younger 

passenger car drivers were in vehicles that rolled over. 

Table 11 

Vehicles in single-vehicle crashes 

by vehicle type, driver age, and rollover status, 1994, 2003, 2004 

Vehicle Type/Age/Rollover Status (#) 1994 2003 2004 

Rolled Over 56,504 52,329 49,524 16 to 24 

Total 402,779 394,802 372,920

Rolled Over 51,606 40,819 41,937 Passenger car 

25 and older 

Total 665,787 559,863 533,328

Rolled Over 2,413 2,172 2,455 16 to 24 

Total 13,946 16,930 16,261

Rolled Over 7,365 8,910 7,859

Van 

25 and older 

Total 75,635 100,163 92,657

Rolled Over 21,702 17,762 18,253 16 to 24 

Total 80,872 77,817 78,168

Rolled Over 28,359 29,014 28,921 Pickup 

25 and older 

Total 172,555 195,594 197,074

Rolled Over 6,474 21,181 21,725 16 to 24 

Total 23,064 66,100 69,326

Rolled Over 11,327 34,930 33,351 Sport Utility Vehicle 

25 and older 

Total 45,798 146,988 162,509

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Age/Rollover Status (%) 1994 2003 2004 

16 to 24 Rolled Over 14 13 13

Passenger car 

25 and older Rolled Over 8 7 8

16 to 24 Rolled Over 17 13 15

Van 

25 and older Rolled Over 10 9 8

16 to 24 Rolled Over 27 23 23

Pickup 

25 and older Rolled Over 16 15 15

16 to 24 Rolled Over 28 32 31

Sport Utility Vehicle 

25 and older Rolled Over 25 24 21

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Younger Drivers and Passengers. Here, we consider single-vehicle crashes in those cases in 

which the vehicle had two occupants, including the driver; we consider the crashes by the age of 
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both the driver and the passenger. Note that younger drivers and younger passengers are defined 

slightly differently. As before, younger drivers are defined as driver between 16 and 24, 

inclusive. Younger passengers are any passengers who were 24 or younger. 

According to Table 12, the presence of a younger passenger did not seem to have a clear 

association with the rollover rate. Consider the situation with older passenger car drivers. In 

2004, when the passenger was younger, the rollover rate was an estimated 13% whereas when 

the passenger was older, the rate was an estimated 7%. Thus, in this case, younger passengers 

were associated with a higher rollover rate. However, in 2003, the relationship was reversed, 

with a 7% rate with younger passengers and 9% rate with older passengers. 

Note the high variability in some of the percentages shown in Table 12. For example, for sport 

utility vehicles with younger drivers and older passengers, the rollover rate was an estimated 

25% in 2003 and an estimated 8% in 2004. As discussed in the Introduction, such high 

variability is due to the low estimated counts, which makes the standard error of the estimate 

high relative to the estimate itself. For instance, in 2003, an estimated 224 sport utility vehicles 

with younger drivers and older passengers rolled over. The standard error of this estimate is 203, 

or 91% of the estimate. If the estimate had been 10 times as large, then its standard error would 

have been only 27% of the estimate. 

Table 12 

Vehicles with two occupants in single-vehicle crashes 

by vehicle type, driver and passenger age, and rollover status, 1994, 2003, 2004 

Vehicle Type/Driver and passenger age/Rollover Status (#) 1994 2003 2004 

Driver 24 and younger/ Rolled Over 11,635 8,494 7,330

Passenger 24 and younger Total 70,119 57,665 52,204

Driver 24 and younger/ Rolled Over 1,139 1,496 836

Passenger 25 and older Total 9,057 9,521 7,400

Driver 25 and older/ Rolled Over 3,353 2,140 3,168

Passenger 24 and younger Total 30,269 30,257 23,675

Rolled Over 5,990 3,893 2,901

Passenger car 

Driver 25 and older/ 

Passenger 25 and older Total 56,112 41,232 42,986

Driver 24 and younger/ Rolled Over 213 52 463

Passenger 24 and younger Total 1,235 1,948 1,965

Driver 24 and younger/ Rolled Over 0 78 141

Passenger 25 and older Total 0 1,157 909

Driver 25 and older/ Rolled Over 76 346 334

Passenger 24 and younger Total 4,083 4,148 5,741

Rolled Over 642 807 889

Van 

Driver 25 and older/ 

Passenger 25 and older Total 5,116 8,257 7,613

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Vehicle Type/Driver and passenger age/Rollover Status (#) 1994 2003 2004 

Driver 24 and younger/ Rolled Over 5,018 3,169 3,175

Passenger 24 and younger Total 16,587 10,858 12,202

Driver 24 and younger/ Rolled Over 1,019 360 508

Passenger 25 and older Total 2,302 1,211 1,032

Driver 25 and older/ Rolled Over 1,657 1,365 1,320

Passenger 24 and younger Total 6,681 7,582 5,875

Rolled Over 2,924 3,052 3,588

Pickup 

Driver 25 and older/ 

Passenger 25 and older Total 15,136 15,234 18,944

Driver 24 and younger/ Rolled Over 1,051 4,337 3,955

Passenger 24 and younger Total 2,984 11,196 9,926

Driver 24 and younger/ Rolled Over 200 224 153

Passenger 25 and older Total 547 893 1,873

Driver 25 and older/ Rolled Over 1,074 2,462 1,740

Passenger 24 and younger Total 1,801 8,601 6,349

Rolled Over 1,936 3,832 3,460

Sport Utility Vehicle 

Driver 25 and older/ 

Passenger 25 and older Total 3,855 12,373 12,633

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Driver and passenger age/Rollover Status (%) 1994 2003 2004 

Driver 24 and younger/ 

Passenger 24 and younger Rolled Over 17 15 14

Driver 24 and younger/ 

Passenger 25 and older Rolled Over 13 16 11

Driver 25 and older/ 

Passenger 24 and younger Rolled Over 11 7 13

Passenger car 

Driver 25 and older/ 

Passenger 25 and older Rolled Over 11 9 7

Driver 24 and younger/ 

Passenger 24 and younger Rolled Over 17 3 24

Driver 24 and younger/ 

Passenger 25 and older Rolled Over - 7 16

Driver 25 and older/ 

Passenger 24 and younger Rolled Over 2 8 6

Van 

Driver 25 and older/ 

Passenger 25 and older Rolled Over 13 10 12

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Vehicle Type/Driver and passenger age/Rollover Status (%) 1994 2003 2004 

Driver 24 and younger/ 

Passenger 24 and younger Rolled Over 30 29 26

Driver 24 and younger/ 

Passenger 25 and older Rolled Over 44 30 49

Driver 25 and older/ 

Passenger 24 and younger Rolled Over 25 18 22

Pickup 

Driver 25 and older/ 

Passenger 25 and older Rolled Over 19 20 19

Driver 24 and younger/ 

Passenger 24 and younger Rolled Over 35 39 40

Driver 24 and younger/ 

Passenger 25 and older Rolled Over 37 25 8

Driver 25 and older/ 

Passenger 24 and younger Rolled Over 60 29 27

Sport Utility Vehicle 

Driver 25 and older/ 

Passenger 25 and older Rolled Over 50 31 27

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Sex. In 2004, an estimated 52,824 of the estimated 534,279 male drivers of passenger cars that 

were in single-vehicle car crashes were in cars that rolled over, which means that the rollover 

rate for male passenger car drivers was 10%. The rollover rate for female passenger car drivers 

was, likewise, 10%. From the numbers in Table 13, there did not seem to be a clear relationship 

between driver sex and the rollover rate. 

Table 13 

Vehicles in single-vehicle crashes 

by vehicle type, driver sex, and rollover status, 1994, 2003, 2004 

Vehicle Type/Sex/Rollover Status (#) 1994 2003 2004 

Rolled Over 65,072 55,407 52,824 Male 

Total 660,456 552,622 534,279

Rolled Over 45,251 39,017 40,030 Passenger car 

Female 

Total 447,327 429,926 400,122

Rolled Over 5,666 7,326 7,190 Male 

Total 59,813 74,292 69,505

Rolled Over 4,276 3,968 3,336

Van 

Female 

Total 34,896 46,868 42,446

(Continued on Next Page) 
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Vehicle Type/Sex/Rollover Status (#) 1994 2003 2004 

Rolled Over 42,476 40,394 40,669 Male 

Total 228,134 240,530 236,890

Rolled Over 8,033 7,104 7,159 Pickup 

Female 

Total 33,689 39,285 44,394

Rolled Over 12,379 32,628 32,730 Male 

Total 48,311 130,162 133,431

Rolled Over 5,774 24,058 23,376 Sport Utility Vehicle 

Female 

Total 21,770 88,002 105,284

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Sex/Rollover Status (%) 1994 2003 2004 

Male Rolled Over 10 10 10

Passenger car 

Female Rolled Over 10 9 10

Male Rolled Over 9 10 10

Van 

Female Rolled Over 12 8 8

Male Rolled Over 19 17 17

Pickup 

Female Rolled Over 24 18 16

Male Rolled Over 26 25 25

Sport Utility Vehicle Female Rolled Over 27 27 22

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Alcohol. Whether alcohol was involved in the crash is derived from police-reported alcohol 

involvement. If any driver, pedestrian, cyclist, or other nonmotorist who was in a crash used 

alcohol, the crash was classified as having alcohol involvement. Note that simply because a crash 

had alcohol involvement does not mean that alcohol use caused the crash. 

In 2004, there were an estimated 106,934 passenger cars in single-vehicle car crashes in which 

alcohol was involved. Of these, an estimated 15,618 passenger cars rolled over. In 2004, the 

passenger car rollover rate when alcohol was involved was thus 15%. When alcohol was not 

involved, the rate was 9%. This relationship that alcohol involvement was associated with higher 

incidence of rollover, held for all vehicle types considered in Table 14. 
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Table 14 

Vehicles in single-vehicle crashes 

by vehicle type, alcohol involvement, and rollover status, 1994, 2003, 2004 

Vehicle Type/Alcohol Involvement/Rollover Status (#) 1994 2003 2004 

Rolled Over 20,652 17,356 15,618 Involved 

Total 132,969 105,693 106,934

Rolled Over 88,740 69,988 72,312 Passenger car 

Not Involved 

Total 970,416 802,783 765,542

Rolled Over 690 1,202 1,293 Involved 

Total 4,872 9,225 7,070

Rolled Over 8,870 9,369 8,944

Van 

Not Involved 

Total 89,430 101,318 96,450

Rolled Over 10,246 9,755 9,418 Involved 

Total 45,655 35,498 37,825

Rolled Over 39,002 35,087 35,889 Pickup 

Not Involved 

Total 215,657 224,900 228,828

Rolled Over 2,814 8,000 8,298 Involved 

Total 8,038 23,400 25,375

Rolled Over 15,066 46,064 44,467 Sport Utility Vehicle 

Not Involved 

Total 60,589 182,124 195,817

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Alcohol Involvement/Rollover Status (%) 1994 2003 2004 

Involved Rolled Over 16 16 15

Passenger car 

Not Involved Rolled Over 9 9 9

Involved Rolled Over 14 13 18

Van 

Not Involved Rolled Over 10 9 9

Involved Rolled Over 22 27 25

Pickup 

Not Involved Rolled Over 18 16 16

Involved Rolled Over 35 34 33

Sport Utility Vehicle Not Involved Rolled Over 25 25 23

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Maneuver Prior to Critical Event. Vehicle maneuver prior to critical event describes a 

vehicle’s activity prior to the driver’s realization of an impending critical event, or just prior to 

impact if the driver took no action or had no time to attempt any evasive maneuvers. 
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As seen in Table 15, by far, most vehicles rolled over while going straight. For example, in 2004, 

an estimated 56,124 passenger cars rolled over while going straight, compared to an estimated 

30,424 passenger car rollovers while negotiating a curve. However, the highest rate of rollover 

occurred while passing. For example, in 2004, 28% of passenger cars that were passing before a 

single-vehicle crash rolled over in that crash. For sport utility vehicles, the rate was 58%. The 

vehicle maneuver associated with the lowest rollover rate was turning. In 2004, only 3% of 

passenger cars that were turning prior to a single-vehicle crash rolled over in that crash. Note that 

the table shows the probability of rollover given involvement in a single-vehicle crash, by type of 

crash. In other words, the table does not say that passing leads to more rollovers than going 

straight. Rather, it says that if a vehicle is involved in a single-vehicle crash while passing, it is 

more likely that it rolls over than if it was involved in a single-vehicle crash while going straight. 

Table 15 

Vehicles in single-vehicle crashes 

by vehicle type, maneuver prior to critical event, and rollover status, 1994, 2003, 2004 

Vehicle Type/Vehicle Maneuver/Rollover Status (#) 1994 2003 2004 

Rolled Over 87,500 59,712 56,124 Going Straight 

Total 884,766 668,273 625,433

Rolled Over 1,391 1,597 1,615 Passing 

Total 7,120 7,403 5,685

Rolled Over 1,892 2,188 2,300 Changing Lanes 

Total 10,723 17,035 15,870

Rolled Over 13,467 30,257 30,424 Negotiating a Curve 

Total 64,266 179,800 168,204

Rolled Over 3,801 2,291 2,045

Passenger car 

Turning 

Total 82,044 76,547 71,818

Rolled Over 8,027 8,014 7,866 Going Straight 

Total 72,686 80,968 77,573

Rolled Over 0 0 0

Passing 

Total 427 1,063 761

Rolled Over 326 287 223

Changing Lanes 

Total 869 981 1,042

Rolled Over 676 2,722 2,388 Negotiating a Curve 

Total 2,362 11,647 9,302

Rolled Over 290 102 144

Van 

Turning 

Total 6,429 9,883 7,524

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Vehicle Type/Vehicle Maneuver/Rollover Status (#) 1994 2003 2004 

Rolled Over 40,700 29,578 30,887 Going Straight 

Total 204,781 191,851 196,088

Rolled Over 434 661 610

Passing 

Total 1,168 2,617 1,700

Rolled Over 649 348 661

Changing Lanes 

Total 2,706 2,968 2,966

Rolled Over 6,742 16,688 13,355 Negotiating a Curve 

Total 19,145 52,126 40,852

Rolled Over 1,355 666 1,775

Pickup 

Turning 

Total 15,230 15,591 18,868

Rolled Over 13,129 37,425 35,787 Going Straight 

Total 54,059 149,284 156,340

Rolled Over 309 510 1,050 Passing 

Total 469 1,519 1,805

Rolled Over 358 985 847

Changing Lanes 

Total 875 2,722 3,145

Rolled Over 2,190 16,379 15,336 Negotiating a Curve 

Total 3,883 37,756 39,243

Rolled Over 1,045 1,169 2,367

Sport Utility Vehicle 

Turning 

Total 4,025 16,465 18,147

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Vehicle Maneuver/Rollover Status (%) 1994 2003 2004 

Going Straight Rolled Over 10 9 9

Passing Rolled Over 20 22 28

Changing Lanes Rolled Over 18 13 14

Negotiating a Curve Rolled Over 21 17 18

Passenger car 

Turning Rolled Over 5 3 3

Going Straight Rolled Over 11 10 10

Passing Rolled Over 0 0 0

Changing Lanes Rolled Over 38 29 21

Negotiating a Curve Rolled Over 29 23 26

Van 

Turning Rolled Over 5 1 2

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Vehicle Type/Vehicle Maneuver/Rollover Status (%) 1994 2003 2004 

Going Straight Rolled Over 20 15 16

Passing Rolled Over 37 25 36

Changing Lanes Rolled Over 24 12 22

Negotiating a Curve Rolled Over 35 32 33

Pickup 

Turning Rolled Over 9 4 9

Going Straight Rolled Over 24 25 23

Passing Rolled Over 66 34 58

Changing Lanes Rolled Over 41 36 27

Negotiating a Curve Rolled Over 56 43 39

Sport Utility Vehicle 

Turning Rolled Over 26 7 13

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Corrective Action Attempted. Corrective action attempted describes actions taken by the driver 

of a vehicle in response to the impending danger. Of the three actions considered in Table 16, 

none, braking, and steering, “none” (meaning no corrective action) was associated with the 

lowest rollover rate given involvement in a single-vehicle crash while steering was associated 

with the highest rollover rate. For example, in passenger cars in single-vehicle crashes in 2004, 

no corrective action was associated with a rollover rate given involvement in a single-vehicle 

crash of an estimated 7%, whereas steering was associated with a rate of an estimated 21%, 3 

times as high. In sport utility vehicles, steering was associated with a 40% probability of rollover 

given involvement in a single-vehicle crash. 

Note however that these results do not imply that taking no corrective action decreased the 

probability of rollover whereas steering increased it. For example, it is possible that drivers chose 

to steer when, in their judgments, the impending crash had a high severity; and that it is these 

crashes of high perceived severity that were associated with a high rollover rate. 

Table 16 

Vehicles in single-vehicle crashes 

by vehicle type, corrective action attempted, and rollover status, 1994, 2003, 2004 

Vehicle Type/Crash Avoidance Maneuver/Rollover Status (#) 1994 2003 2004 

Rolled Over 66,935 4,407 9,623 None 

Total 856,770 84,320 146,810

Rolled Over 19,106 3,483 3,788 Braking 

Total 106,721 47,218 43,336

Rolled Over 18,773 26,308 29,726

Passenger car 

Steering 

Total 108,707 155,434 141,971

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Vehicle Type/Crash Avoidance Maneuver/Rollover Status (#) 1994 2003 2004 

Rolled Over 6,910 169 1,474 None 

Total 82,584 13,255 18,539

Rolled Over 792 521 404

Braking 

Total 4,218 3,594 2,637

Rolled Over 1,963 2,556 2,146

Van 

Steering 

Total 6,758 12,311 12,406

Rolled Over 31,941 1,991 4,107 None 

Total 207,529 22,994 40,975

Rolled Over 8,533 2,060 1,607 Braking 

Total 27,188 12,004 13,536

Rolled Over 7,694 11,288 12,555

Pickup 

Steering 

Total 22,417 40,376 41,689

Rolled Over 12,570 3,034 7,094 None 

Total 52,275 17,329 36,146

Rolled Over 1,790 3,434 1,835 Braking 

Total 6,544 10,303 7,926

Rolled Over 2,298 13,794 13,864

Sport Utility Vehicle 

Steering 

Total 7,557 34,212 35,051

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Crash Avoidance Maneuver/Rollover Status (%) 1994 2003 2004 

None Rolled Over 8 5 7

Passenger car Braking Rolled Over 18 7 9

Steering Rolled Over 17 17 21

None Rolled Over 8 1 8

Van Braking Rolled Over 19 14 15

Steering Rolled Over 29 21 17

None Rolled Over 15 9 10

Pickup Braking Rolled Over 31 17 12

Steering Rolled Over 34 28 30

None Rolled Over 24 18 20

Sport Utility Vehicle Braking Rolled Over 27 33 23

Steering Rolled Over 30 40 40

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 
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Other Factors 

Vehicle Occupancy. According to Table 17, in 2004 an estimated 825,888 passenger cars in 

single-vehicle car crashes had one or two occupants, counting the driver. Of these, an estimated 

81,509 passenger cars rolled over, making the passenger car rollover rate given involvement in a 

single-vehicle crash when there were one or two occupants 10%. When there were three to five 

occupants, again, counting the driver, the rate increased to 13%. For all vehicle types under 

consideration, higher occupancy was associated with a higher rollover rate. For example, pickups 

with six or more occupants had a probability of 54% of rolling over given involvement in a 

single-vehicle crash. The result that higher occupancy is associated with higher probability of 

rollover in a single-vehicle crash is confirmed by multivariate analysis later in this report, as well 

as by other analyses, such as Subramanian (2005). One possible reason for this is that higher 

occupancy raises the vehicle’s center of mass, which makes it less stable. 

Table 17 

Vehicles in single-vehicle crashes 

by vehicle type, number of vehicle occupants, and rollover status, 1994, 2003, 2004 

Vehicle Type/Number of Vehicle Occupants/Rollover Status (#) 1994 2003 2004 

Rolled Over 96,499 82,307 81,509 1 or 2 

Total 1,047,772 864,373 825,888

Rolled Over 16,603 10,425 10,526 3 to 5 

Total 116,418 87,006 78,110

Rolled Over 937 112 502

Passenger car 

6 or more 

Total 4,910 1,813 1,526

Rolled Over 7,456 8,463 7,994 1 or 2 

Total 85,994 99,746 89,756

Rolled Over 2,065 2,294 1,918 3 to 5 

Total 13,037 14,174 15,223

Rolled Over 421 378 597

Van 

6 or more 

Total 1,772 1,852 2,380

Rolled Over 47,178 43,518 43,474 1 or 2 

Total 256,645 256,536 256,325

Rolled Over 4,240 3,380 3,812 3 to 5 

Total 16,133 16,505 15,712

Rolled Over 705 109 136

Pickup 

6 or more 

Total 1,562 401 250

Rolled Over 15,776 48,311 47,449 1 or 2 

Total 65,449 187,154 203,131

Rolled Over 2,288 6,948 8,086 3 to 5 

Total 7,697 22,267 24,800

Rolled Over 90 724 467

Sport Utility Vehicle 

6 or more 

Total 235 1,475 1,070

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 
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Vehicle Type/Number of Vehicle Occupants/Rollover Status (%) 1994 2003 2004 

1 or 2 Rolled Over 9 10 10

Passenger car 3 to 5 Rolled Over 14 12 13

6 or more Rolled Over 19 6 33

1 or 2 Rolled Over 9 8 9

Van 3 to 5 Rolled Over 16 16 13

6 or more Rolled Over 24 20 25

1 or 2 Rolled Over 18 17 17

Pickup 3 to 5 Rolled Over 26 20 24

6 or more Rolled Over 45 27 54

1 or 2 Rolled Over 24 26 23

Sport Utility Vehicle 3 to 5 Rolled Over 30 31 33

6 or more Rolled Over 38 49 44

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Speed Limit. As Table 18 shows, in 2004 when the speed limit was 30 mph or less, there were 

an estimated 201,660 single-vehicle car crashes, an estimated 6,889 of which resulted in a 

rollover. Thus, at these speed limits, the probability of passenger car rollover given involvement 

in a single-vehicle crash was 3%. The probability increased with increasing speed limits. At a 

speed limit of 60 mph or higher, the probability for passenger cars was 16%, which is 5.3 times 

(= [16% ÷ 3%]) as much as it was at 30 mph or less. At a speed limit of 30 mph or less, the 

probability of rollover given involvement in a single-vehicle crash for utility vehicles was 15%, 

which was about twice as high as it was for pickups (at 7%), almost four times as high as it was 

for vans (at 4%), and five times as high as it was for passenger cars (at 3%). 

Table 18 

Vehicles in single-vehicle crashes 

by vehicle type, posted speed limit, and rollover status, 1994, 2003, 2004 

Vehicle Type/Speed Limit/Rollover Status (#) 1994 2003 2004 

Rolled Over 10,581 8,000 6,889 30 mph or less 

Total 280,396 220,262 201,660

Rolled Over 80,019 58,595 57,598 35 to 55 mph 

Total 616,563 491,210 466,218

Rolled Over 6,894 20,349 20,784

Passenger car 

60 mph or more 

Total 38,588 125,140 126,227

Rolled Over 282 1,313 855 30 mph or less 

Total 23,640 30,600 23,817

Rolled Over 6,212 5,856 5,695 35 to 55 mph 

Total 47,705 53,156 53,706

Rolled Over 1,866 3,451 3,484

Van 

60 mph or more 

Total 5,186 15,548 13,508

(Continued on Next Page) 
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Vehicle Type/Speed Limit/Rollover Status (#) 1994 2003 2004

Rolled Over 2,897 3,812 3,962 30 mph or less 

Total 57,817 53,932 54,877

Rolled Over 39,543 30,060 28,146 35 to 55 mph 

Total 173,613 158,684 160,338

Rolled Over 3,225 11,134 12,683

Pickup 

60 mph or more 

Total 10,716 45,319 42,082

Rolled Over 2,518 7,493 7,978 30 mph or less 

Total 18,342 47,264 51,764

Rolled Over 12,163 31,350 29,209 35 to 55 mph 

Total 38,985 117,039 127,285

Rolled Over 1,359 16,171 16,416

Sport Utility Vehicle 

60 mph or more 

Total 2,875 40,636 40,951

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/Speed Limit/Rollover Status (%) 1994 2003 2004 

30 mph or less Rolled Over 4 4 3

Passenger car 35 to 55 mph Rolled Over 13 12 12

60 mph or more Rolled Over 18 16 16

30 mph or less Rolled Over 1 4 4

Van 35 to 55 mph Rolled Over 13 11 11

60 mph or more Rolled Over 36 22 26

30 mph or less Rolled Over 5 7 7

Pickup 35 to 55 mph Rolled Over 23 19 18

60 mph or more Rolled Over 30 25 30

30 mph or less Rolled Over 14 16 15

Sport Utility Vehicle 35 to 55 mph Rolled Over 31 27 23

60 mph or more Rolled Over 47 40 40

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Road Type. As seen in Table 19, in 2004, most single-vehicle car rollovers occurred on 

undivided two-way trafficways, with an estimated 59,962 rollovers. The highest rollover rate, 

however, was on divided highways, with an estimated 12% of all single-vehicle car crashes 

involving a rollover. This higher probability of rollover on divided highways could have been 

due to several reasons. It could have been due to the road type itself, or due to some other 

variable. For instance, it could have been due to the fact that divided highways generally have 

higher speed limits. Another interesting issue is the high rollover rate that occurred on one-way 

roads. For example, in 2004, the rate for sport utility vehicles was 31%. Addressing these two 
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issues requires multivariate analysis, such as logistic analysis presented later in this report. See 

there for a further discussion. 

Table 19 

Vehicles in single-vehicle crashes 

by vehicle type, road type, and rollover status, 1994, 2003, 2004 

Vehicle Type/Type of Road/Rollover Status (#) 1994 2003 2004 

Rolled Over 72,558 60,963 59,962 Undivided Two-Way 

Total 656,551 586,269 568,469

Rolled Over 24,830 24,460 24,951 Divided Highway 

Total 197,615 204,495 203,790

Rolled Over 3,599 3,631 2,225

Passenger car 

One-way 

Total 37,805 44,366 36,253

Rolled Over 4,850 5,788 6,057 Undivided Two-Way 

Total 48,415 66,264 67,253

Rolled Over 3,121 4,244 4,025 Divided Highway 

Total 16,859 22,934 22,899

Rolled Over 347 255 257

Van 

One-way 

Total 2,862 4,849 2,433

Rolled Over 35,894 33,960 29,211 Undivided Two-Way 

Total 173,271 182,687 183,342

Rolled Over 8,328 10,064 13,584 Divided Highway 

Total 36,871 55,313 57,497

Rolled Over 1,486 1,185 1,723

Pickup 

One-way 

Total 6,258 8,756 8,116

Rolled Over 10,088 32,326 31,149 Undivided Two-Way 

Total 41,079 128,952 144,820

Rolled Over 4,197 19,980 18,716 Divided Highway 

Total 13,307 56,525 58,817

Rolled Over 777 1,933 2,473

Sport Utility Vehicle 

One-way 

Total 3,239 6,750 7,933

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 
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Vehicle Type/Type of Road/Rollover Status (%) 1994 2003 2004 

Undivided Two-Way Rolled Over 11 10 11

Passenger car Divided Highway Rolled Over 13 12 12

One-way Rolled Over 10 8 6

Undivided Two-Way Rolled Over 10 9 9

Van Divided Highway Rolled Over 19 19 18

One-way Rolled Over 12 5 11

Undivided Two-Way Rolled Over 21 19 16

Pickup Divided Highway Rolled Over 23 18 24

One-way Rolled Over 24 14 21

Undivided Two-Way Rolled Over 25 25 22

Sport Utility Vehicle Divided Highway Rolled Over 32 35 32

One-way Rolled Over 24 29 31

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Relation to junction. By “relation to junction,” we mean whether the first harmful event of the 

crash occurred in an interchange and whether it occurred in an intersection. These categories are 

based on the REL_JCT variable in GES. The variable is classified into the interchange/noninterchange and intersection/non-intersection categories following NHTSA c (2004) and Lindsey 

(2006). In particular, NHTSA c (2004) classifies some values of the variable as referring to an 

interchange and others as referring to a non-interchange area. Lindsey classifies “intersection” 

and “intersection-related” as intersection, and all other values that are not unknown as nonintersection. Interchange is an area with roadways on different levels, such as a cloverleaf; noninterchange is an area in which all roadways are on the same level. An intersection consists of 

two or more roadways that intersect at the same level. 

According to Table 20, given involvement in a single-vehicle crash, rollovers were more likely 

to occur in non-intersections as opposed to intersections. For example, in 2004, the rollover rate 

for passenger cars given involvement in a single-vehicle crash in non-interchange intersections 

was only an estimated 3%; compare this to an estimated 11% rate on non-interchange nonintersections. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 20 

Vehicles in single-vehicle crashes 

by vehicle type, relation to junction, and rollover status, 1994, 2003, 2004 

Vehicle Type/Relation to Junction/Rollover Status (#) 1994 2003 2004 

Non-Interchange Rolled Over 104,953 87,873 88,088

Non-Intersection Total 998,578 842,440 808,669

Non-Interchange Rolled Over 5,270 4,637 3,328

Intersection Total 147,829 145,877 131,339

Interchange Rolled Over 2,902 4,986 3,182

Non-Intersection Total 19,297 38,892 31,034

Rolled Over 409 92 52

Passenger car 

Interchange Intersection 

Total 3,128 1,259 984

Non-Interchange Rolled Over 9,129 10,192 10,121

Non-Intersection Total 87,505 105,612 101,996

Non-Interchange Rolled Over 536 818 427

Intersection Total 11,751 19,058 13,568

Interchange Rolled Over 184 397 568

Non-Intersection Total 776 4,192 2,154

Rolled Over 93 0 0

Van 

Interchange Intersection 

Total 93 0 0

Non-Interchange Rolled Over 49,019 45,511 44,372

Non-Intersection Total 245,035 257,371 253,231

Non-Interchange Rolled Over 1,971 1,771 2,985

Intersection Total 25,750 24,963 30,440

Interchange Rolled Over 796 1,699 1,345

Non-Intersection Total 4,018 8,364 6,713

Rolled Over 244 0 0

Pickup 

Interchange Intersection 

Total 436 0 0

Non-Interchange Rolled Over 16,372 52,197 50,048

Non-Intersection Total 61,990 192,066 208,439

Non-Interchange Rolled Over 1,341 2,847 3,472

Intersection Total 9,335 26,464 25,919

Interchange Rolled Over 441 2,430 3,016

Non-Intersection Total 1,642 6,846 9,118

Rolled Over 0 0 142

Sport Utility Vehicle 

Interchange Intersection 

Total 0 0 377

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Vehicle Type/Relation to Junction/Rollover Status (%) 1994 2003 2004 

Non-Interchange 

Non-Intersection Rolled Over 11 10 11

Non-Interchange 

Intersection Rolled Over 4 3 3

Interchange 

Non-Intersection Rolled Over 15 13 10

Passenger car 

Interchange Intersection Rolled Over 13 7 5

Non-Interchange 

Non-Intersection Rolled Over 10 10 10

Non-Interchange 

Intersection Rolled Over 5 4 3

Interchange 

Non-Intersection Rolled Over 24 9 26

Van 

Interchange Intersection Rolled Over 100 - -

Non-Interchange 

Non-Intersection Rolled Over 20 18 18

Non-Interchange 

Intersection Rolled Over 8 7 10

Interchange 

Non-Intersection Rolled Over 20 20 20

Pickup 

Interchange Intersection Rolled Over 56 - -

Non-Interchange 

Non-Intersection Rolled Over 26 27 24

Non-Interchange 

Intersection Rolled Over 14 11 13

Interchange 

Non-Intersection Rolled Over 27 35 33

Sport Utility Vehicle 

Interchange Intersection Rolled Over - - 38

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

First Harmful Event. The first harmful event is the first property-damaging or injury-producing 

event in a crash as judged by GES coders based on police crash reports. 

In 2004, there were an estimated 37,953 passenger cars in single-car crashes for which the first 

harmful event was a rollover. Considering the other first harmful events shown in Table 21, the 

highest rollover rate for passenger cars given involvement in a single-vehicle crash was 

associated with striking an embankment, at an estimated 30%, followed by hitting a culvert, 

curb, or ditch, at an estimated 17%. Striking an embankment had the highest rollover rate for the 

other vehicle types as well. For example, for pickups in 2004, striking an embankment was 

associated with a rollover rate given involvement in a single-vehicle crash of 52%. The lowest 

rollover rates were for other non-collisions and for striking an object not fixed. It is also 

interesting to note striking a guard rail or a barrier as the first harmful event resulted in a higher 

rollover rate for pickups (an estimated 13%) and utility vehicles (15%) than for passenger cars 

(5%) and vans (8%). 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 21 

Vehicles in single-vehicle crashes 

by vehicle type, first harmful event, and rollover status, 1994, 2003, 2004 

Vehicle Type/First Harmful Event/Rollover Status (#) 1994 2003 2004 

Rolled Over 49,725 37,003 37,953 Rollover 

Total 49,725 37,003 37,953

Rolled Over 291 9 127

Other Non-collision 

Total 19,176 9,611 7,763

Rolled Over 1,073 4,242 2,055 Object Not Fixed 

Total 484,832 403,789 372,402

Rolled Over 545 562 230

Bridge 

Total 9,163 10,502 8,933

Rolled Over 5,733 7,390 6,079 Guard Rail/Barrier 

Total 96,756 109,781 110,789

Rolled Over 1,598 1,425 1,908 Fence 

Total 34,428 28,240 29,010

Rolled Over 5,038 9,353 6,079 Pole/Post 

Total 129,699 140,256 117,962

Rolled Over 27,810 17,869 20,788 Culvert/Curb/Ditch 

Total 135,820 118,639 119,031

Rolled Over 9,745 9,363 8,964 Embankment 

Total 39,601 35,514 29,993

Rolled Over 6,065 6,036 5,687

Passenger car 

Shrubbery/Tree 

Total 89,311 87,350 87,060

Rolled Over 5,418 6,123 6,163 Rollover 

Total 5,418 6,123 6,163

Rolled Over 83 0 0

Other Non-collision 

Total 2,392 0 0

Rolled Over 142 578 206

Object Not Fixed 

Total 58,596 75,595 71,001

Rolled Over 0 95 0

Bridge 

Total 0 533 0

Rolled Over 893 373 606

Guard Rail/Barrier 

Total 5,788 6,763 7,870

Rolled Over 219 113 123

Van 

Fence 

Total 1,487 3,906 1,284

(Continued on Next Page) 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Vehicle Type/First Harmful Event/Rollover Status (#) 1994 2003 2004 

Rolled Over 229 755 685

Pole/Post 

Total 10,198 12,224 8,883

Rolled Over 1,663 2,311 1,783 Culvert/Curb/Ditch 

Total 6,286 8,485 6,451

Rolled Over 889 370 846

Embankment 

Total 2,083 1,918 2,517

Rolled Over 81 475 514

Van 

Shrubbery/Tree 

Total 3,386 7,120 6,472

Rolled Over 26,391 23,278 25,391 Rollover 

Total 26,391 23,278 25,391

Rolled Over 99 951 52

Other Non-collision 

Total 9,623 8,732 8,667

Rolled Over 224 765 427

Object Not Fixed 

Total 94,415 113,372 111,193

Rolled Over 189 254 448

Bridge 

Total 3,473 2,268 2,450

Rolled Over 1,651 3,229 3,492 Guard Rail/Barrier 

Total 15,893 26,886 26,007

Rolled Over 491 1,236 995 Fence 

Total 9,730 9,318 9,915

Rolled Over 1,963 2,868 2,305 Pole/Post 

Total 27,945 31,672 32,822

Rolled Over 9,894 8,786 6,858 Culvert/Curb/Ditch 

Total 29,351 28,056 27,614

Rolled Over 5,606 3,814 4,804 Embankment 

Total 11,321 10,271 9,160

Rolled Over 2,302 2,258 2,942

Pickup 

Shrubbery/Tree 

Total 23,631 24,584 24,992

Rolled Over 9,549 29,310 31,830 Rollover 

Total 9,549 29,310 31,830

Rolled Over 236 87 95

Other Non-collision 

Total 1,042 2,811 4,028

Rolled Over 412 1,137 1,729 Object Not Fixed 

Total 26,944 81,180 83,789

Rolled Over 73 803 142

Sport Utility Vehicle 

Bridge 

Total 1,245 3,471 2,593

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Vehicle Type/First Harmful Event/Rollover Status (#) 1994 2003 2004 

Rolled Over 825 4,711 4,047 Guard Rail/Barrier 

Total 5,141 21,030 26,477

Rolled Over 6 356 870

Fence 

Total 1,400 3,724 5,468

Rolled Over 720 2,573 2,840 Pole/Post 

Total 8,916 24,034 25,131

Rolled Over 3,603 10,847 7,105 Culvert/Curb/Ditch 

Total 7,193 25,873 23,085

Rolled Over 1,610 3,645 3,105 Embankment 

Total 2,775 7,829 8,626

Rolled Over 192 2,213 2,844

Sport Utility Vehicle 

Shrubbery/Tree 

Total 3,982 17,297 22,012

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Vehicle Type/First Harmful Event/Rollover Status (%) 1994 2003 2004 

Rollover Rolled Over 100 100 100

Other Non-collision Rolled Over 2 0 2

Object Not Fixed Rolled Over 0 1 1

Bridge Rolled Over 6 5 3

Guard Rail/Barrier Rolled Over 6 7 5

Fence Rolled Over 5 5 7

Pole/Post Rolled Over 4 7 5

Culvert/Curb/Ditch Rolled Over 20 15 17

Embankment Rolled Over 25 26 30

Passenger car 

Shrubbery/Tree Rolled Over 7 7 7

Rollover Rolled Over 100 100 100

Other Non-collision Rolled Over 3 - -

Object Not Fixed Rolled Over 0 1 0

Bridge Rolled Over - 18 -

Guard Rail/Barrier Rolled Over 15 6 8

Fence Rolled Over 15 3 10

Pole/Post Rolled Over 2 6 8

Culvert/Curb/Ditch Rolled Over 26 27 28

Embankment Rolled Over 43 19 34

Van 

Shrubbery/Tree Rolled Over 2 7 8

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Vehicle Type/First Harmful Event/Rollover Status (%) 1994 2003 2004 

Rollover Rolled Over 100 100 100

Other Non-collision Rolled Over 1 11 1

Object Not Fixed Rolled Over 0 1 0

Bridge Rolled Over 5 11 18

Guard Rail/Barrier Rolled Over 10 12 13

Fence Rolled Over 5 13 10

Pole/Post Rolled Over 7 9 7

Culvert/Curb/Ditch Rolled Over 34 31 25

Embankment Rolled Over 50 37 52

Pickup 

Shrubbery/Tree Rolled Over 10 9 12

Rollover Rolled Over 100 100 100

Other Non-collision Rolled Over 23 3 2

Object Not Fixed Rolled Over 2 1 2

Bridge Rolled Over 6 23 5

Guard Rail/Barrier Rolled Over 16 22 15

Fence Rolled Over 0 10 16

Pole/Post Rolled Over 8 11 11

Culvert/Curb/Ditch Rolled Over 50 42 31

Embankment Rolled Over 58 47 36

Sport Utility Vehicle 

Shrubbery/Tree Rolled Over 5 13 13

Source: NHTSA, NCSA, GES, 1994, 2003, 2004. 

Discussion. The rollover propensity tables show the probability that a vehicle rolled over given 

that it was involved in a single-vehicle crash. These tables generally show that, given 

involvement in a single-vehicle crash, sport utility vehicles were more likely to roll over than 

pickups, which in turn were more likely to roll over than either vans or passenger cars. Vehicles 

that were more likely to roll over were older, were driven by younger unbelted drivers, had more 

occupants, and were in speed-related crashes on divided highways with higher speed limits, in 

non-intersection areas. Alcohol involvement increased the probability of rollover. Vehicles that 

were more likely to roll over (a) were passing as opposed to turning prior to the single-vehicle 

crash; (b) had drivers who attempted to steer when they realized that the crash was imminent; 

and (c) had the first harmful event in the single-vehicle crash of either rollover or striking an 

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

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6. Injury Outcomes 

This section considers injury severity and ejection status of occupants who were in vehicles that 

rolled over in single-vehicle crashes. The tables show annual data for 2004, the latest year for 

which data are available, 2003, the previous year, and 1994, which is 10 years prior to 2004, or 

the earliest year available if it is later than 1994. Since all the data in this section is occupantlevel, it comes from a combination of the FARS and the GES databases. Specifically, the data on 

occupants who were fatally injured is from the FARS database, while the data on occupants who 

were not fatally injured is from the GES database. 

Rather than considering occupants in single-vehicle rollovers, one logical possibility was to 

consider occupants in crashes in which rollover was classified as the most harmful event. The 

most harmful event is the most severe property-damaging or injury-producing event for each 

vehicle as judged by FARS analysts and GES coders based on police crash reports. However, 

Griffin et al. (2002), which studied vehicle fires, found that the most harmful event variable in 

FARS was coded very inconsistently across States. For example, the paper found that in some 

States, whenever a vehicle fire occurred, the most harmful event was classified as fire; whereas 

in other States, the most harmful event was never classified as fire, even though there were 

plenty of vehicles in the FARS database for that State in which fires have occurred. The paper 

concluded that such extreme variation across States was most probably due to variations in the 

reporting procedures related to the most harmful event variable. It is for this reason that we do 

not use the most harmful event variable. 

In the FARS and GES databases, injury severity, as taken from Police Accident Reports (PARs), 

is given on the KABCO scale. In the tables and discussions below, fatality corresponds a K 

(“Fatal Injury”) on the scale, incapacitating injury to an A (“Incapacitating Injury”), other injury 

to a B (“Non-incapacitating Evident Injury”), C (“Possible Injury”), or U (“Injured, Severity 

Unknown”), and no injury to an O (“No Injury”). 

Note that the percentage tables in this section show the proportion of people with each possible 

type of injury. Thus, the percentages in the tables do add up to 100%. 

Injury Severity by Vehicle Type. As Table 22 shows, in 2004, for the vehicle types considered, 

passenger cars had the highest number of occupants killed in single-vehicle rollovers, at 3,640 

occupants. The next highest fatality count was for sport utility vehicles, at 2,331. The fatality rate 

given involvement in a single-vehicle rollover was similar for all four vehicle groups, between 

2% and 3%. However, the rate of no injuries was higher in pickups and sport utility vehicles than 

it was in passenger cars and vans. For example, the “no injury” rate given involvement in a 

single-vehicle rollover in sport utility vehicles was an estimated 43%, compared to an estimated 

39% for passenger cars. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 22 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type and injury severity, 1994, 2003, 2004 

Vehicles Type/Injury Severity (#) 1994 2003 2004 

Fatal 4,072 3,752 3,640

Incapacitating Injury 27,644 15,731 16,374

Other Injury 79,692 74,940 66,079

No Injury 76,349 47,560 54,460

Passenger car 

Total 187,756 141,983 140,553

Fatal 434 521 487

Incapacitating Injury 1,555 2,722 1,985

Other Injury 6,033 9,819 10,957

No Injury 11,266 7,922 8,238

Van 

Total 19,288 20,984 21,667

Fatal 1,969 2,130 2,100

Incapacitating Injury 9,616 7,556 7,817

Other Injury 30,927 29,874 30,074

No Injury 37,738 28,257 29,268

Pickup 

Total 80,250 67,817 69,259

Fatal 841 2,120 2,331

Incapacitating Injury 4,486 11,653 11,381

Other Injury 11,244 39,208 38,324

No Injury 13,409 39,222 39,284

Sport Utility Vehicle 

Total 29,980 92,203 91,320

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Vehicles Type/Injury Severity (%) 1994 2003 2004 

Fatal 2 3 3

Incapacitating Injury 15 11 12

Other Injury 42 53 47 Passenger car 

No Injury 41 33 39

Fatal 2 2 2

Incapacitating Injury 8 13 9

Other Injury 31 47 51

Van 

No Injury 58 38 38

Fatal 2 3 3

Incapacitating Injury 12 11 11

Other Injury 39 44 43 Pickup 

No Injury 47 42 42

(Continued on Next Page) 
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Vehicles Type/Injury Severity (%) 1994 2003 2004 

Fatal 3 2 3

Incapacitating Injury 15 13 12

Other Injury 38 43 42 Sport Utility Vehicle 

No Injury 45 43 43

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Injury Severity in Fatal Single-Vehicle Rollovers by Vehicle Type. In Table 23, we consider 

the same information as above, but restrict it only to fatal crashes. A fatal crash is defined as a 

crash that involves at least one fatality, whether occupant or nonoccupant. It may be of interest to 

consider fatal crashes as opposed to all crashes since fatal crashes are more severe. One should 

be cautious when considering probabilities of injury in fatal crashes, since, by definition, the 

probability of death in a fatal single-vehicle crash with a single occupant and no nonoccupant 

fatalities is 100%. As vans might have generally had more occupants than other vehicle types, it 

is not surprising that the probability of death in a fatal crash was lower for vans than it was for 

other vehicle types. 

In 2004, 4,777 occupants were in passenger cars that were involved in fatal single-vehicle 

rollovers. Of these, 3,640, or 76%, were fatally injured. By contrast, the fatality rate given 

involvement in a fatal single-vehicle rollover in vans was 43%. Since this table only uses the 

FARS database, it contains actual counts, not estimates. Note that a few of the counts of nonfatally injured occupants were zero. This is simply because the table is restricted to fatal 

rollovers. As we see from the percentages, the overwhelming majority (in the case of passenger 

cars and pickups) or at least a very sizable minority (for vans and sport utility vehicles) of 

occupants died in such rollovers. 

Table 23 Occupants of vehicles in fatal single-vehicle rollovers 

by vehicle type and injury severity, 1994, 2003, 2004 

Vehicles Type/Injury Severity (#) 1994 2003 2004 

Fatal 4,072 3,752 3,640

Incapacitating Injury 1,826 406 626

Other Injury 415 574 471

No Injury 71 10 40

Passenger car 

Total 6,384 4,742 4,777

Fatal 434 521 487

Incapacitating Injury 0 629 280

Other Injury 321 75 271

No Injury 321 3 86

Van 

Total 1,076 1,229 1,124

Fatal 1,969 2,130 2,100

Incapacitating Injury 578 446 335

Other Injury 131 306 191

No Injury 0 5 64

Pickup 

Total 2,678 2,887 2,689

Fatal 841 2,120 2,331

Incapacitating Injury 568 670 1,109

Other Injury 386 1,312 927

No Injury 0 27 151

Sport Utility Vehicle 

Total 1,796 4,129 4,518

Source: NHTSA, NCSA, FARS, 1994, 2003, 2004. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Vehicles Type/Injury Severity (%) 1994 2003 2004 

Fatal 64 79 76

Incapacitating Injury 29 9 13

Other Injury 6 12 10 Passenger car 

No Injury 1 0 1

Fatal 40 42 43

Incapacitating Injury 0 51 25

Other Injury 30 6 24

Van 

No Injury 30 0 8

Fatal 74 74 78

Incapacitating Injury 22 15 12

Other Injury 5 11 7 Pickup 

No Injury 0 0 2

Fatal 47 51 52

Incapacitating Injury 32 16 25

Other Injury 22 32 21 Sport Utility Vehicle 

No Injury 0 1 3

Source: NHTSA, NCSA, FARS, 1994, 2003, 2004. 

Ejection Status by Vehicle Type. Ejection status considers whether an occupant was totally 

ejected from the vehicle. For years 1990 – 1994, GES does not code total ejections. Therefore, 

all tables involving ejection status begin in 1995 rather than 1994. 

As seen in Table 24, in 2004, an estimated 91,320 occupants were in sport utility vehicles that 

were in single-vehicle rollovers. Of these, an estimated 5,050 occupants were totally ejected 

from their vehicles, making the total ejection rate given involvement in single-vehicle rollover 

for sport utility vehicle occupants 6%. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 24 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type and ejection status, 1995, 2003, 2004 

Vehicles Type/Ejection Status (#) 1995 2003 2004 

Total Ejection 5,075 5,775 5,280 Passenger car Total 178,075 141,983 140,553

Total Ejection 833 806 680

Van 

Total 20,187 20,984 21,667

Total Ejection 3,156 3,710 2,855 Pickup Total 78,112 67,817 69,259

Total Ejection 1,627 4,206 5,050 Sport Utility Vehicle Total 33,823 92,203 91,320

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 

Vehicles Type/Ejection Status (%) 1995 2003 2004 

Passenger car Total Ejection 3 4 4

Van Total Ejection 4 4 3

Pickup Total Ejection 4 5 4

Sport Utility Vehicle Total Ejection 5 5 6

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 

Restraint Use by Vehicle Type. Restraint use is as reported by the police. It may reflect selfreporting by occupants of vehicles that crashed, and might thus be a biased estimate of actual 

restraint use. 

According to Table 25, the rate of restraint use has gone up over the years in all four vehicle 

types under consideration. For example, in 1994, an estimated 64% of occupants of passenger 

cars in single-vehicle crashes used restraints. This rate was an estimated 77% in 2004. It is 

interesting to compare these restraint use rates for occupants of vehicles involved in singlevehicle rollovers to restraint use rates for occupants of all vehicles. According to Glassbrenner 

and Ye (2006), which uses the National Occupant Protection Use Survey (NOPUS) database, in 

1994, an estimated 58% of vehicle occupants across the United States used vehicle restraints. In 

2003, the use rate was an estimated 79%; in 2004, it was an estimated 80%. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 25 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type and restraint use, 1994, 2003, 2004 

Vehicles Type/Restraint Use (#) 1994 2003 2004 

Restrained 119,299 102,463 108,748 Passenger car Total 187,756 141,983 140,553

Restrained 12,404 17,370 17,435 Van 

Total 19,288 20,984 21,667

Restrained 41,951 48,181 51,134 Pickup Total 80,250 67,817 69,259

Restrained 18,186 72,586 71,943 Sport Utility Vehicle Total 29,980 92,203 91,320

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Vehicles Type/Restraint Use (%) 1994 2003 2004 

Passenger car Restrained 64 72 77

Van Restrained 64 83 80

Pickup Restrained 52 71 74

Sport Utility Vehicle Restrained 61 79 79

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Injury Severity by Occupant Restraint. As Table 26 shows, in single-vehicle rollovers in 

2004, 949 passenger car occupants who used restraints were killed. As there were an estimated 

108,748 restrained passenger car occupants in single-vehicle rollovers, the fatality rate for 

restrained occupants was 1%. By contrast, 2,487 unrestrained passenger car occupants were 

fatally injured in single-vehicle rollovers; the fatality rate for unrestrained passenger car 

occupants was thus an estimated 13%. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

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Table 26 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type, restraint use, and injury severity, 1994, 2003, 2004 

Vehicle Type/Restraint Use/Injury Severity (#) 1994 2003 2004 

Fatal 852 1,037 949

Incapacitating Injury 12,373 9,458 10,593

Other Injury 52,136 52,122 49,113

No Injury 53,938 39,847 48,093

Restrained 

Total 119,299 102,463 108,748

Fatal 2,972 2,499 2,487

Incapacitating Injury 13,758 5,244 4,888

Other Injury 18,635 12,004 9,349

No Injury 8,186 4,136 2,974

Passenger car 

Unrestrained 

Total 43,552 23,883 19,698

Fatal 63 116 105

Incapacitating Injury 966 1,881 1,201

Other Injury 3,553 8,487 8,552

No Injury 7,823 6,886 7,577

Restrained 

Total 12,404 17,370 17,435

Fatal 346 372 360

Incapacitating Injury 589 774 508

Other Injury 2,209 773 1,574

No Injury 1,867 738 405

Van 

Unrestrained 

Total 5,011 2,657 2,847

Fatal 209 357 440

Incapacitating Injury 2,752 3,765 4,970

Other Injury 16,484 19,824 21,846

No Injury 22,506 24,235 23,879

Restrained 

Total 41,951 48,181 51,134

Fatal 1,665 1,684 1,586

Incapacitating Injury 6,045 3,604 2,424

Other Injury 10,124 5,327 5,340

No Injury 7,873 2,946 2,171

Pickup 

Unrestrained 

Total 25,707 13,561 11,522

(Continued on Next Page) 
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Vehicle Type/Restraint Use/Injury Severity (#) 1994 2003 2004 

Fatal 159 520 605

Incapacitating Injury 2,116 7,562 7,197

Other Injury 7,067 29,558 29,671

No Injury 8,844 34,946 34,470

Restrained 

Total 18,186 72,586 71,943

Fatal 646 1,499 1,634

Incapacitating Injury 1,985 3,661 3,697

Other Injury 3,601 6,194 5,884

No Injury 2,049 2,257 3,035

Sport Utility Vehicle 

Unrestrained 

Total 8,280 13,611 14,250

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Vehicle Type/Restraint Use/Injury Severity (%) 1994 2003 2004 

Fatal 1 1 1

Incapacitating Injury 10 9 10

Other Injury 44 51 45

Restrained 

No Injury 45 39 44

Fatal 7 10 13

Incapacitating Injury 32 22 25

Other Injury 43 50 47

Passenger car 

Unrestrained 

No Injury 19 17 15

Fatal 1 1 1

Incapacitating Injury 8 11 7

Other Injury 29 49 49

Restrained 

No Injury 63 40 43

Fatal 7 14 13

Incapacitating Injury 12 29 18

Other Injury 44 29 55

Van 

Unrestrained 

No Injury 37 28 14

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Vehicle Type/Restraint Use/Injury Severity (%) 1994 2003 2004 

Fatal 0 1 1

Incapacitating Injury 7 8 10

Other Injury 39 41 43

Restrained 

No Injury 54 50 47

Fatal 6 12 14

Incapacitating Injury 24 27 21

Other Injury 39 39 46

Pickup 

Unrestrained 

No Injury 31 22 19

Fatal 1 1 1

Incapacitating Injury 12 10 10

Other Injury 39 41 41

Restrained 

No Injury 49 48 48

Fatal 8 11 11

Incapacitating Injury 24 27 26

Other Injury 43 46 41

Sport Utility Vehicle 

Unrestrained 

No Injury 25 17 21

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Ejection Status by Occupant Restraint. The contrast between restrained and unrestrained 

occupants was even greater when considered by ejection status rather than fatality outcome. As 

seen in Table 27, in 2004 single-vehicle rollovers, an estimated 1% of the restrained passenger 

car occupants were totally ejected, as compared to an estimated 22% of the unrestrained 

occupants. In sport utility vehicles, a very small percentage of the restrained occupants were 

totally ejected; the rate for unrestrained sport utility vehicle occupants was 33%. Note also that 

the total ejection rate for unrestrained occupants has increased dramatically for all vehicle types 

from 1995 to 2003. For example, in 1995, the rate for van occupants was an estimated 10%, 

while in 2003, it was an estimated 24%. 

Table 27 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type, restraint use, and ejection status, 1995, 2003, 2004 

Vehicle Type/Restraint Use/Ejection Status (#) 1995 2003 2004 

Total Ejection 648 679 660

Restrained 

Total 117,418 102,463 108,748

Total Ejection 4,058 4,706 4,327 Passenger car 

Unrestrained 

Total 42,732 23,883 19,698

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Vehicle Type/Restraint Use/Ejection Status (#) 1995 2003 2004 

Total Ejection 227 164 12

Restrained 

Total 12,297 17,370 17,435

Total Ejection 592 625 655

Van 

Unrestrained 

Total 6,223 2,657 2,847

Total Ejection 224 154 99

Restrained 

Total 42,568 48,181 51,134

Total Ejection 2,784 3,457 2,677 Pickup 

Unrestrained 

Total 21,574 13,561 11,522

Total Ejection 19 328 239

Restrained 

Total 21,143 72,586 71,943

Total Ejection 1,432 3,649 4,662 Sport Utility Vehicle 

Unrestrained 

Total 9,992 13,611 14,250

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 

Vehicle Type/Restraint Use/Ejection Status (%) 1995 2003 2004 

Restrained Total Ejection 1 1 1

Passenger car 

Unrestrained Total Ejection 9 20 22

Restrained Total Ejection 2 1 0

Van 

Unrestrained Total Ejection 10 24 23

Restrained Total Ejection 1 0 0

Pickup 

Unrestrained Total Ejection 13 25 23

Restrained Total Ejection 0 0 0

Sport Utility Vehicle Unrestrained Total Ejection 14 27 33

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 

Ejection Status in Fatal Crashes by Occupant Restraint. According to Table 28, even in fatal 

crashes, ejection status was strongly associated with restraint use. In fatal single-vehicle rollovers 

that occurred in 2004, 5% of the restrained passenger car occupants were totally ejected, as 

compared to 55% of the unrestrained passenger car occupants. Likewise, the total ejection rate 

for restrained sport utility vehicle occupants was 9%, compared to 65% for unrestrained sport 

utility vehicle occupants. 
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Table 28 

Occupant of vehicles in fatal single-vehicle rollovers 

by vehicle type, restraint use, and ejection status 1995, 2003, 2004 

Vehicle Type/Restraint Use/Ejection Status (#) 1995 2003 2004 

Total Ejection 121 140 74

Restrained 

Total 1,891 1,779 1,560

Total Ejection 1,972 1,593 1,642 Passenger car 

Unrestrained 

Total 3,518 2,649 2,976

Total Ejection 8 69 12

Restrained 

Total 942 578 573

Total Ejection 260 443 249

Van 

Unrestrained 

Total 1,081 611 519

Total Ejection 12 17 24

Restrained 

Total 424 565 659

Total Ejection 1,299 1,377 1,049 Pickup 

Unrestrained 

Total 2,053 2,234 1,887

Total Ejection 19 52 162

Restrained 

Total 391 1,197 1,848

Total Ejection 785 1,587 1,503 Sport Utility Vehicle 

Unrestrained 

Total 960 2,771 2,313

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 

Vehicle Type/Restraint Use/Ejection Status (%) 1995 2003 2004 

Restrained Total Ejection 6 8 5

Passenger car 

Unrestrained Total Ejection 56 60 55

Restrained Total Ejection 1 12 2

Van 

Unrestrained Total Ejection 24 73 48

Restrained Total Ejection 3 3 4

Pickup 

Unrestrained Total Ejection 63 62 56

Restrained Total Ejection 5 4 9

Sport Utility Vehicle Unrestrained Total Ejection 82 57 65

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 

Injury Severity by Ejection Status and Occupant Restraint. Following Digges and Eigen 

(2003) and Eigen (2005), we consider injury severity by both ejection status and occupant 

restraint. This allows us to consider the effects of restraint use on injury outcome controlling for 

ejection status. Alternatively, it allows us to consider the effects of total ejection on injury 

outcome controlling for restraint use. 
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As Table 29 shows, in 2004, among occupants of passenger cars that rolled over in singlevehicle crashes, of those who used restraints and were not totally ejected, one percent were 

fatally injured. Of the occupants who did use restraints but who were nevertheless totally ejected, 

the fatality rate was 11%. Of the occupants who were not totally ejected even though they did not 

use restraints, 7% were fatally injured. Finally, of the passenger car occupants who did not use 

restraints and were totally ejected, the fatality rate was 35%. These results illustrate that there 

was an interaction effect between restraint use and ejection status in determining injury 

outcomes. In particular, even if an occupant was totally ejected, being restrained decreased the 

probability of fatality. 

Table 29 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type, restraint and ejection status, and injury severity, 1995, 2003, 2004 

Vehicle Type/Restraint and Total Ejection Status/Injury Severity (#) 1995 2003 2004 

Fatal 1,877 1,519 1,512

Incapacitating Injury 2,001 1,895 1,548

Other Injury 180 1,292 1,267

Total 

Ejection/Unrestrained 

Total 4,058 4,706 4,327

Fatal 1,183 974 962

Incapacitating Injury 7,790 3,218 2,980

Other Injury 19,521 9,289 7,204

No Injury 10,047 4,136 2,974

No or Partial 

Ejection/Unrestrained 

Total 38,541 17,616 14,119

Fatal 121 88 74

Incapacitating Injury 237 236 379

Other Injury 290 355 207

Total 

Ejection/Restrained 

Total 648 679 660

Fatal 785 949 873

Incapacitating Injury 12,132 8,402 9,298

Other Injury 53,726 46,212 43,433

No Injury 50,123 39,847 48,093

Passenger car 

No or Partial 

Ejection/Restrained 

Total 116,766 95,410 101,697

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Vehicle Type/Restraint and Total Ejection Status/Injury Severity (#) 1995 2003 2004 

Fatal 260 267 238

Incapacitating Injury 242 340 180

Other Injury 89 17 237

Total 

Ejection/Unrestrained 

Total 592 625 655

Fatal 90 101 122

Incapacitating Injury 1,198 353 322

Other Injury 2,617 621 1,047

No Injury 1,724 738 343

No or Partial 

Ejection/Unrestrained 

Total 5,629 1,813 1,835

Fatal 8 14 12

Incapacitating Injury 219 55 0

Other Injury 0 95 0

Total 

Ejection/Restrained 

Total 227 164 12

Fatal 55 102 92

Incapacitating Injury 1,130 1,314 1,035

Other Injury 4,971 6,860 6,114

No Injury 5,914 6,443 7,577

Van 

No or Partial 

Ejection/Restrained 

Total 12,070 14,718 14,819

Fatal 1,169 1,097 1,028

Incapacitating Injury 927 1,544 845

Other Injury 688 816 803

No Injury 0 0 4

Total Ejection / 

Unrestrained 

Total 2,784 3,457 2,680

Fatal 658 582 555

Incapacitating Injury 2,837 1,573 1,207

Other Injury 10,053 3,716 3,415

No Injury 5,235 2,946 2,167

No or Partial Ejection / 

Unrestrained 

Total 18,782 8,817 7,344

Fatal 12 17 24

Incapacitating Injury 212 43 75

Other Injury 0 95 0

Total Ejection / 

Restrained 

Total 224 154 99

Fatal 176 340 418

Incapacitating Injury 3,408 3,252 4,077

Other Injury 18,619 14,558 16,722

No Injury 20,141 24,235 23,879

Pickup 

No or Partial Ejection / 

Restrained 

Total 42,343 42,385 45,096

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52 

Fatal 590 1,132 1,223

Incapacitating Injury 559 1,595 2,021

Other Injury 154 922 1,418

No Injury 130 0 0

Total 

Ejection/Unrestrained 

Total 1,432 3,649 4,662

Fatal 172 359 405

Incapacitating Injury 1,230 1,568 1,669

Other Injury 5,135 3,796 3,191

No Injury 2,021 2,257 3,035

No or Partial 

Ejection/Unrestrained 

Total 8,557 7,980 8,301

Fatal 19 48 39

Incapacitating Injury 0 119 165

Other Injury 0 161 35

Total 

Ejection/Restrained 

Total 19 328 239

Fatal 160 471 565

Incapacitating Injury 776 6,775 5,859

Other Injury 9,348 25,488 24,925

No Injury 10,840 34,946 34,470

Sport Utility Vehicle 

No or Partial 

Ejection/Restrained 

Total 21,124 67,679 65,818

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 
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Vehicle Type/Restraint and Total Ejection Status/Injury Severity (%) 1995 2003 2004 

Fatal 46 32 35

Incapacitating 

Injury 49 40 36

Other Injury 4 27 29

Total Ejection/Unrestrained No Injury 0 0 0

Fatal 3 6 7

Incapacitating 

Injury 20 18 21

Other Injury 51 53 51 No or Partial 

Ejection/Unrestrained No Injury 26 23 21

Fatal 19 13 11

Incapacitating 

Injury 37 35 57

Other Injury 45 52 31

Total Ejection/Restrained No Injury 0 0 0

Fatal 1 1 1

Incapacitating 

Injury 10 9 9

Passenger Other Injury 46 48 43

car No or Partial Ejection/Restrained No Injury 43 42 47

Fatal 44 43 36

Incapacitating 

Injury 41 55 27

Other Injury 15 3 36

Total Ejection/Unrestrained No Injury 0 0 0

Fatal 2 6 7

Incapacitating 

Injury 21 19 18

Other Injury 46 34 57 No or Partial 

Ejection/Unrestrained No Injury 31 41 19

Fatal 4 9 100

Incapacitating 

Injury 96 34 0

Other Injury 0 58 0

Total Ejection/Restrained No Injury 0 0 0

Fatal 0 1 1

Incapacitating 

Injury 9 9 7

Other Injury 41 47 41

Van No or Partial Ejection/Restrained No Injury 49 44 51

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Vehicle Type/Restraint and Total Ejection Status/Injury Severity 

(%) 1995 2003 2004 

Fatal 42 32 38 

Incapacitating Injury 33 45 32 

Other Injury 25 24 30 Total 

Ejection/Unrestrained No Injury 0 0 0 

Fatal 4 7 8 

Incapacitating Injury 15 18 16 

Other Injury 54 42 46 No or Partial 

Ejection/Unrestrained No Injury 28 33 30 

Fatal 5 11 24 

Incapacitating Injury 95 28 76 

Other Injury 0 61 0 Total 

Ejection/Restrained No Injury 0 0 0 

Fatal 0 1 1 

Incapacitating Injury 8 8 9 

Other Injury 44 34 37 

Pickup 

No or Partial 

Ejection/Restrained No Injury 48 57 53 

Fatal 41 31 26 

Incapacitating Injury 39 44 43 

Other Injury 11 25 30 Total 

Ejection/Unrestrained No Injury 9 0 0 

Fatal 2 4 5 

Incapacitating Injury 14 20 20 

Other Injury 60 48 38 No or Partial 

Ejection/Unrestrained No Injury 24 28 37 

Fatal 100 15 16 

Incapacitating Injury 0 36 69 

Other Injury 0 49 15 Total 

Ejection/Restrained No Injury 0 0 0 

Fatal 1 1 1 

Incapacitating Injury 4 10 9 

Other Injury 44 38 38 

Sport 

Utility 

Vehicle 

No or Partial 

Ejection/Restrained No Injury 51 52 52 

Source: NHTSA, NCSA, FARS, GES, 1995, 2003, 2004. 

Note: Ejection Status data available starting in 1995 
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Injury Severity by Occupant Age. According to Table 30, in 2004, the fatality rate of singlevehicle rollover occupants 4 years old and younger was an estimated 1%. The rate increased with 

age. For example, for occupants 35 to 44 years old, the fatality rate was an estimated 3%; for 

occupants 75 and older, the fatality rate was 10%. 

Table 30 

Occupants of vehicles in single-vehicle rollovers 

by occupant age and injury severity, 1994, 2003, 2004 

Age/Injury Severity (#) 1994 2003 2004 

Fatal 119 113 111

Incapacitating Injury 855 317 603

Other Injury 2,333 3,237 3,672

No Injury 4,246 3,412 3,461

4 and Younger 

Total 7,553 7,079 7,848

Fatal 55 91 114

Incapacitating Injury 431 732 625

Other Injury 1,715 3,044 3,247

No Injury 2,820 2,150 2,677

5 to 9 

Total 5,021 6,017 6,663

Fatal 314 324 276

Incapacitating Injury 3,286 1,632 1,880

Other Injury 8,516 8,409 9,741

No Injury 7,264 5,551 6,797

10 to 15 

Total 19,379 15,915 18,693

Fatal 1,545 1,710 1,746

Incapacitating Injury 12,257 10,841 9,845

Other Injury 41,489 43,932 40,545

No Injury 42,157 36,361 37,182

16 to 20 

Total 97,448 92,844 89,317

Fatal 1,060 1,184 1,209

Incapacitating Injury 5,934 4,349 5,233

Other Injury 14,077 20,739 18,864

No Injury 15,790 17,126 19,158

21 to 24 

Total 36,862 43,398 44,464

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Age/Injury Severity (#) 1994 2003 2004 

Fatal 1,691 1,617 1,647

Incapacitating Injury 9,509 6,905 7,061

Other Injury 25,008 24,530 24,869

No Injury 24,739 21,229 23,877

25 to 34 

Total 60,947 54,281 57,454

Fatal 1,095 1,355 1,287

Incapacitating Injury 5,229 5,513 5,385

Other Injury 14,632 19,818 18,426

No Injury 13,415 15,697 14,412

35 to 44 

Total 34,370 42,382 39,510

Fatal 648 984 1,015

Incapacitating Injury 2,915 4,221 3,531

Other Injury 6,572 9,739 11,020

No Injury 8,196 10,660 8,826

45 to 54 

Total 18,330 25,603 24,391

Fatal 344 554 575

Incapacitating Injury 1,040 1,895 1,648

Other Injury 3,088 5,488 6,525

No Injury 3,267 4,787 4,290

55 to 64 

Total 7,739 12,724 13,038

Fatal 287 324 312

Incapacitating Injury 740 818 1,102

Other Injury 2,159 2,599 2,391

No Injury 2,354 1,491 2,235

65 to 74 

Total 5,540 5,232 6,040

Fatal 178 259 247

Incapacitating Injury 670 434 478

Other Injury 1,055 2,073 1,330

No Injury 93 963 412

75 and older 

Total 1,996 3,729 2,467

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 
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Age/Injury Severity (%) 1994 2003 2004 

Fatal 2 2 1

Incapacitating Injury 11 4 8

Other Injury 31 46 47 4 and younger 

No Injury 56 48 44

Fatal 1 2 2

Incapacitating Injury 9 12 9

Other Injury 34 51 49

5 to 9 

No Injury 56 36 40

Fatal 2 2 1

Incapacitating Injury 17 10 10

Other Injury 44 53 52

10 to 15 

No Injury 37 35 36

Fatal 2 2 2

Incapacitating Injury 13 12 11

Other Injury 43 47 45

16 to 20 

No Injury 43 39 42

Fatal 3 3 3

Incapacitating Injury 16 10 12

Other Injury 38 48 42

21 to 24 

No Injury 43 39 43

Fatal 3 3 3

Incapacitating Injury 16 13 12

Other Injury 41 45 43

25 to 34 

No Injury 41 39 42

Fatal 3 3 3

Incapacitating Injury 15 13 14

Other Injury 43 47 47

35 to 44 

No Injury 39 37 36

Fatal 4 4 4

Incapacitating Injury 16 16 14

Other Injury 36 38 45

45 to 54 

No Injury 45 42 36

Fatal 4 4 4

Incapacitating Injury 13 15 13

Other Injury 40 43 50

55 to 64 

No Injury 42 38 33

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Age/Injury Severity (%) 1994 2003 2004 

Fatal 5 6 5

Incapacitating Injury 13 16 18

Other Injury 39 50 40

65 to 74 

No Injury 42 28 37

Fatal 9 7 10

Incapacitating Injury 34 12 19

Other Injury 53 56 54

75 and older 

No Injury 5 26 17

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Use of Child Safety Seats. In looking at child safety seats, we follow NHTSA b (2004) and only 

consider occupants who were 4 years old or younger. According to Lindsey (2006), historically, 

NCSA typically classified a child safety seat used improperly as a child safety seat not used; 

however, starting in mid 2003, NCSA typically classifies a child safety seat used improperly as a 

child safety seat used. We follow the more recent practice and classify “child safety seat used 

improperly” as a child safety seat used for all the years under consideration. 

As with general restraint use, child safety seat use has gone up since 1994. For example, as Table 

31 shows, in 1994 single-vehicle rollovers, an estimated 56% of the children 4 years old or 

younger who were occupants in passenger cars used child safety seat. This rate has increased to 

an estimated 78% in 2004. 

Table 31 

Occupants 4 years old or younger of vehicles in single-vehicle rollovers 

by vehicle type and use of child safety seat, 1994, 2003, 2004 

Vehicles Type/Use of Child Safety Seat (#) 1994 2003 2004 

Used 2,689 1,937 2,784 Passenger car Total 4,836 2,333 3,551

Used 280 770 716

Van 

Total 922 1,268 952

Used 332 92 478

Pickup Total 1,134 218 695

Used 322 2,840 1,669 Sport Utility Vehicle Total 659 3,260 2,546

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 
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Vehicles Type/Use of Child Safety Seat (%) 1994 2003 2004 

Passenger car Used 56 83 78

Van Used 30 61 75

Pickup Used 29 42 69

Sport Utility Vehicle Used 49 87 66

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Injury Severity by Use of Child Safety Seats. As seen in Table 32, in 2004, of the children 4 

years old or younger who were occupants in passenger cars that rolled over in a single-vehicle 

crash, an estimated 2,784 were using a child safety seat while an estimated 652 were not using 

such a seat. Of those children who were using a child safety seat, 1% was fatally injured, while 

of those who were not using such a seat, 3% were fatally injured. 

Table 32 

Occupants 4 years old and younger of vehicles in single-vehicle rollovers 

by vehicle type, use of child safety seats, and injury severity, 1994, 2003, 2004 

Vehicle Type/Use of Child Safety Seat/Injury Severity (#) 1994 2003 2004 

Fatal 15 35 22

Incapacitating Injury 212 17 168

Other Injury 706 1,084 1,354

No Injury 1,756 800 1,240

Used 

Total 2,689 1,937 2,784

Fatal 53 18 20

Incapacitating Injury 195 11 86

Other Injury 997 106 300

No Injury 848 143 246

Passenger car 

Not used 

Total 2,093 279 652

Fatal 4 3 6

Incapacitating Injury 151 143 0

Other Injury 0 78 229

No Injury 125 546 481

Used 

Total 280 770 716

Fatal 9 11 8

Incapacitating Injury 94 20 0

Other Injury 0 378 213

No Injury 377 89 14

Van 

Not used 

Total 481 497 235

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Vehicle Type/Use of Child Safety Seat/Injury Severity (#) 1994 2003 2004 

Fatal 4 2 2

Incapacitating Injury 0 0 0

Other Injury 73 0 0

No Injury 255 90 476

Used 

Total 332 92 478

Fatal 15 3 13

Incapacitating Injury 203 0 4

Other Injury 114 123 133

No Injury 470 0 67

Pickup 

Not used 

Total 802 126 216

Fatal 5 13 13

Incapacitating Injury 0 39 112

Other Injury 201 1,181 887

No Injury 116 1,607 657

Used 

Total 322 2,840 1,669

Fatal 11 24 21

Incapacitating Injury 0 87 195

Other Injury 190 210 408

No Injury 137 98 154

Sport Utility Vehicle 

Not used 

Total 337 419 778

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Vehicle Type/Use of Child Safety Seat/Injury Severity (%) 1994 2003 2004 

Fatal 1 2 1

Incapacitating Injury 8 1 6

Other Injury 26 56 49

Used 

No Injury 65 41 45

Fatal 3 6 3

Incapacitating Injury 9 4 13

Other Injury 48 38 46

Passenger car 

Not used 

No Injury 41 51 38

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Vehicle Type/Use of Child Safety Seat/Injury Severity (%) 1994 2003 2004 

Fatal 1 0 1

Incapacitating Injury 54 19 0

Other Injury 0 10 32

Used 

No Injury 45 71 67

Fatal 2 2 3

Incapacitating Injury 20 4 0

Other Injury 0 76 91

Van 

Not used 

No Injury 79 18 6

Fatal 1 2 0

Incapacitating Injury 0 0 0

Other Injury 22 0 0

Used 

No Injury 77 98 100

Fatal 2 2 6

Incapacitating Injury 25 0 2

Other Injury 14 98 61

Pickup 

Not used 

No Injury 59 0 31

Fatal 2 0 1

Incapacitating Injury 0 1 7

Other Injury 62 42 53

Used 

No Injury 36 57 39

Fatal 3 6 3

Incapacitating Injury 0 21 25

Other Injury 56 50 52

Sport Utility Vehicle 

Not used 

No Injury 41 23 20

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Injury Severity by Sex. According to Table 33, in 2004 there were an estimated 76,517 male 

occupants of passenger cars and an estimated 59,111 female occupants of passenger cars who 

were in single-vehicle rollovers. The fatality rate for males was 3% whereas for females it was 

2%. On the other hand, 42% of all males suffered no injury, while only 33% of all females did 

not have any injuries. 
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Table 33 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type, sex, and injury severity, 1994, 2003, 2004 

Vehicle Type/Sex/Injury Severity (#) 1994 2003 2004 

Fatal 2,706 2,527 2,437

Incapacitating Injury 16,113 8,767 7,895

Other Injury 41,505 37,066 34,054

No Injury 40,705 29,979 32,130

Male 

Total 101,029 78,338 76,517

Fatal 1,362 1,225 1,203

Incapacitating Injury 11,530 6,964 8,427

Other Injury 33,804 34,543 30,169

No Injury 26,322 15,855 19,313

Passenger car 

Female 

Total 73,018 58,587 59,111

Fatal 277 320 321

Incapacitating Injury 660 1,459 1,308

Other Injury 3,068 4,968 6,196

No Injury 5,919 5,582 5,558

Male 

Total 9,923 12,330 13,383

Fatal 157 201 166

Incapacitating Injury 895 1,254 676

Other Injury 2,871 4,747 4,152

No Injury 4,788 2,008 2,628

Van 

Female 

Total 8,711 8,210 7,623

Fatal 1,637 1,779 1,740

Incapacitating Injury 7,157 5,954 6,118

Other Injury 23,712 21,403 21,823

No Injury 25,649 23,309 23,309

Male 

Total 58,155 52,445 52,990

Fatal 332 351 360

Incapacitating Injury 2,459 1,597 1,698

Other Injury 5,719 6,944 7,211

No Injury 7,998 3,900 4,350

Pickup 

Female 

Total 16,507 12,793 13,620

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Vehicle Type/Sex/Injury Severity (#) 1994 2003 2004 

Fatal 587 1,314 1,439

Incapacitating Injury 2,734 5,481 5,526

Other Injury 6,411 20,441 21,485

No Injury 9,113 22,327 22,058

Male 

Total 18,845 49,562 50,508

Fatal 254 806 892

Incapacitating Injury 1,752 6,172 5,851

Other Injury 4,833 17,990 15,982

No Injury 3,599 15,391 14,452

Sport Utility Vehicle 

Female 

Total 10,438 40,359 37,177

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004. 

Vehicle Type/Sex/Injury Severity (%) 1994 2003 2004 

Fatal 3 3 3

Incapacitating Injury 16 11 10

Other Injury 41 47 45

Male 

No Injury 40 38 42

Fatal 2 2 2

Incapacitating Injury 16 12 14

Other Injury 46 59 51

Passenger car 

Female 

No Injury 36 27 33

Fatal 3 3 2

Incapacitating Injury 7 12 10

Other Injury 31 40 46

Male 

No Injury 60 45 42

Fatal 2 2 2

Incapacitating Injury 10 15 9

Other Injury 33 58 54

Van 

Female 

No Injury 55 24 34

Fatal 3 3 3

Incapacitating Injury 12 11 12

Other Injury 41 41 41

Male 

No Injury 44 44 44

Fatal 2 3 3

Incapacitating Injury 15 12 12

Other Injury 35 54 53

Pickup 

Female 

No Injury 48 30 32

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Vehicle Type/Sex/Injury Severity (%) 1994 2003 2004 

Fatal 3 3 3

Incapacitating Injury 15 11 11

Other Injury 34 41 43

Male 

No Injury 48 45 44

Fatal 2 2 2

Incapacitating Injury 17 15 16

Other Injury 46 45 43

Sport Utility Vehicle 

Female 

No Injury 34 38 39

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004.. 

Injury Severity by Vehicle Age. As Table 34 shows, in 2004 the fatality rate for occupants of 

passenger cars that were less than 5 years old and that were in single-vehicle rollovers was an 

estimated 2%; for older passenger cars, the fatality rate was an estimated 3%. The fatality rates 

were either 2% or 3% for all four vehicle types under consideration, both for newer and older 

vehicles, in 1994, 2003, and 2004. Thus, there appears to have been no association between 

vehicle age and fatal injury outcomes. 

Table 34 

Occupants of vehicles in single-vehicle rollovers 

by vehicle type, vehicle age, and injury severity, 1994, 2003, 2004 

Vehicle Type/Vehicle Age/Injury Severity (#) 1994 2003 2004 

Fatal 1,270 1,124 996

Incapacitating Injury 9,856 4,552 5,167

Other Injury 26,026 21,689 17,728

No Injury 23,414 14,450 17,764

Less than 5 Years 

Total 60,565 41,815 41,655

Fatal 2,802 2,621 2,628

Incapacitating Injury 17,788 11,169 11,207

Other Injury 53,666 53,018 48,351

No Injury 52,935 33,101 36,453

Passenger car 

5 Years or More 

Total 127,191 99,909 98,639

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Vehicle Type/Vehicle Age/Injury Severity (#) 1994 2003 2004 

Fatal 190 153 126

Incapacitating Injury 1,004 876 576

Other Injury 2,482 2,271 2,854

No Injury 4,287 1,969 3,050

Less than 5 Years 

Total 7,963 5,270 6,605

Fatal 244 368 361

Incapacitating Injury 551 1,846 1,409

Other Injury 3,551 7,548 8,103

No Injury 6,980 5,952 5,188

Van 

5 Years or More 

Total 11,326 15,715 15,061

Fatal 598 811 780

Incapacitating Injury 3,062 3,441 3,525

Other Injury 8,753 10,910 11,952

No Injury 12,035 11,114 10,161

Less than 5 Years 

Total 24,448 26,275 26,419

Fatal 1,371 1,316 1,316

Incapacitating Injury 6,554 4,115 4,291

Other Injury 22,173 18,965 17,962

No Injury 25,703 17,143 19,107

Pickup 

5 Years or More 

Total 55,801 41,539 42,676

Fatal 331 895 845

Incapacitating Injury 1,970 4,685 3,861

Other Injury 3,617 14,753 15,485

No Injury 6,087 15,534 14,906

Less than 5 Years 

Total 12,006 35,867 35,097

Fatal 510 1,224 1,478

Incapacitating Injury 2,516 6,968 7,521

Other Injury 7,627 24,455 22,839

No Injury 7,322 23,688 24,378

Sport Utility Vehicle 

5 Years or More 

Total 17,974 56,335 56,215

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004.. 
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Vehicle Type/Vehicle Age/Injury Severity (%) 1994 2003 2004 

Fatal 2 3 2

Incapacitating Injury 16 11 12

Other Injury 43 52 43

Less than 5 Years 

No Injury 39 35 43

Fatal 2 3 3

Incapacitating Injury 14 11 11

Other Injury 42 53 49

Passenger car 

5 Years or More 

No Injury 42 33 37

Fatal 2 3 2

Incapacitating Injury 13 17 9

Other Injury 31 43 43

Less than 5 Years 

No Injury 54 37 46

Fatal 2 2 2

Incapacitating Injury 5 12 9

Other Injury 31 48 54

Van 

5 Years or More 

No Injury 62 38 34

Fatal 2 3 3

Incapacitating Injury 13 13 13

Other Injury 36 42 45

Less than 5 Years 

No Injury 49 42 38

Fatal 2 3 3

Incapacitating Injury 12 10 10

Other Injury 40 46 42

Pickup 

5 Years or More 

No Injury 46 41 45

Fatal 3 2 2

Incapacitating Injury 16 13 11

Other Injury 30 41 44

Less than 5 Years 

No Injury 51 43 42

Fatal 3 2 3

Incapacitating Injury 14 12 13

Other Injury 42 43 41

Sport Utility Vehicle 

5 Years or More 

No Injury 41 42 43

Source: NHTSA, NCSA, FARS, GES, 1994, 2003, 2004.. 

Discussion. This section considered injury outcomes in single-vehicle rollovers. The data show 

that sport utility vehicles had the highest total ejection rate. Unrestrained occupants had more 

severe injuries and were totally ejected at a higher rate than restrained occupants. There was an 

interaction effect between restraint use and ejection status in determining injury outcomes. In 
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particular, even if an occupant was totally ejected, being restrained decreased the probability of 

fatality. Older male occupants had a higher fatality rate than younger female occupants. 

7. Fatalities Only 

The data used in this section is exclusively from the FARS database and not from the GES 

database. This is because the variables discussed in this section appear only in FARS and not in 

GES. Thus, this section only considers fatally injured occupants, and does not consider 

occupants who were not fatally injured. Data on non-fatally injured occupants from FARS is not 

used. The tables show annual data for 2004, the latest year for which data are available, and 

2003, the previous year. The tables in the Weight, Height, and Body Mass Index subsection also 

show data for year 1998, the earliest year for which data is available; the tables in the Fatalities 

by State subsection also show data for 1994, which is 10 years prior to 2004. 

Weight, Height, and Body Mass Index 

This subsection considers weight, height, and Body Mass Index (BMI) of fatally injured drivers 

in single-vehicle rollovers. It considers drivers rather than all occupants because only the data on 

drivers are available. BMI is a function of weight and height, and is defined below. One reason 

to consider these variables is that it might be thought that they influence the effectiveness and the 

use of seat belts. In particular, people who weigh more, are shorter, or both (that is, those with a 

higher Body Mass Index) are sometimes thought to receive less benefit from using a seat belt and 

are thought to use seat belts less frequently. 

McDowell et al. (2005) tabulates various anthropometric characteristics of the U.S. population as 

it existed between 1999 and 2002. Specifically, it gives certain percentiles of weight, height, and 

BMI for adults 20 and older, by sex. Likewise, the following tables show fatalities by sex, and 

only if they were 20 or older at the time of the crash. The tables use ranges such that each range 

contained 25% of the general population between 1999 and 2002. 

Every year from 1998, the first year on which weight and height of fatally injured drivers was 

collected, until 2004 there have been about 5,000 fatally injured drivers 20 or older in singlevehicle rollovers. The following tables only show the drivers with known seat belt use and 

known weight and/or height, as appropriate. 

Weight. According to NHTSA d (2004), either the driver licensing files or the coroner’s report 

may be used to determine driver weight. Table 35 shows fatally injured drivers 20 or older in 

single-vehicle rollovers by sex, restraint use, and body weight. In such fatalities, there was a 

tendency for restrained drivers to be heavier than unrestrained drivers. For example, in 2004, of 

the male drivers who were restrained, 17% were over 212 lbs, while of those unrestrained, only 

14% were over 212 lbs. 

Regardless of restraint use, these fatally injured drivers tended to be lighter than the general 

population. For example, among unrestrained female driver fatalities in 2004, 32% were 132 lbs 

or less; by contrast, only 25% of the general female population was 132 lbs or less. 
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Table 35 

Fatally injured drivers 20 years old or older in single-vehicle rollovers 

by sex, restraint use, and weight, 1998, 2003, 2004 

Female Drivers 

Restraint Use/Weight (lbs) (#) 1998 2003 2004 

<= 132.5 (25% of population) 102 119 119

132.5 - 154.8 (25% of population) 109 146 170

154.8 - 184.6 (25% of population) 52 72 76

> 184.6 (25% of population) 18 55 57

Restrained 

Total 281 392 422

<= 132.5 (25% of population) 305 268 255

132.5 - 154.8 (25% of population) 312 320 321

154.8 - 184.6 (25% of population) 94 126 124

> 184.6 (25% of population) 60 90 88

Unrestrained 

Total 771 804 788

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Female Drivers 

Restraint Use/Weight (lbs) (%) 1998 2003 2004 

<= 132.5 (25% of population) 36 30 28

132.5 - 154.8 (25% of population) 39 37 40

154.8 - 184.6 (25% of population) 19 18 18

Restrained 

> 184.6 (25% of population) 6 14 14

<= 132.5 (25% of population) 40 33 32

132.5 - 154.8 (25% of population) 40 40 41

154.8 - 184.6 (25% of population) 12 16 16

Unrestrained 

> 184.6 (25% of population) 8 11 11

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).
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Male Drivers 

Restraint Use/Weight (lbs) (#) 1998 2003 2004 

<= 162.3 (25% of population) 165 197 181

162.3 - 184 (25% of population) 266 331 358

184 - 212.1 (25% of population) 145 179 208

> 212.1 (25% of population) 74 111 151

Restrained 

Total 650 818 898

<= 162.3 (25% of population) 715 692 661

162.3 - 184 (25% of population) 1,095 1,117 1,087

184 - 212.1 (25% of population) 548 569 552

> 212.1 (25% of population) 289 351 381

Unrestrained 

Total 2,647 2,729 2,681

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Male Drivers 

Restraint Use/Weight (lbs) (%) 1998 2003 2004 

<= 162.3 (25% of population) 25 24 20

162.3 - 184 (25% of population) 41 40 40

184 - 212.1 (25% of population) 22 22 23

Restrained 

> 212.1 (25% of population) 11 14 17

<= 162.3 (25% of population) 27 25 25

162.3 - 184 (25% of population) 41 41 41

184 - 212.1 (25% of population) 21 21 21

Unrestrained 

> 212.1 (25% of population) 11 13 14

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Height. According to NHTSA d (2004), either the driver licensing files or the coroner’s report 

may be used to determine driver height. Among male drivers who were fatally injured in singlevehicle rollovers, restrained drivers tended to be taller than unrestrained drivers. For example, as 

seen in Table 36, in 2004, 33% of the male restrained fatalities were over 71 inches (5 feet 11 

inches), compared to 29% of the unrestrained fatalities. This pattern appears to have been weak 

or nonexistent among female fatalities. 

Regardless of restraint use, fatally injured drivers in single-vehicle rollovers tended to be taller 

than the general population. For example, in 2004, 38% of the female restrained fatalities were 

taller than 65 inches (5 feet 5 inches), compared to 25% of such females in the general 

population. 
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Table 36 

Fatally injured drivers 20 years old or older in single-vehicle rollovers 

by sex, restraint use, and height, 1998, 2003, 2004 

Female Drivers 

Restraint Use/Height (in) (#) 1998 2003 2004 

<= 62 (25% of population) 67 83 101

62 - 63.8 (25% of population) 39 55 58

63.8 - 65.6 (25% of population) 81 99 101

> 65.6 (25% of population) 94 155 162

Restrained 

Total 281 392 422

<= 62 (25% of population) 176 210 188

62 - 63.8 (25% of population) 129 112 96

63.8 - 65.6 (25% of population) 203 218 210

> 65.6 (25% of population) 263 264 294

Unrestrained 

Total 771 804 788

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Female Drivers 

Restraint Use/Height (in) (%) 1998 2003 2004 

<= 62 (25% of population) 24 21 24

62 - 63.8 (25% of population) 14 14 14

63.8 - 65.6 (25% of population) 29 25 24

Restrained 

> 65.6 (25% of population) 33 40 38

<= 62 (25% of population) 23 26 24

62 - 63.8 (25% of population) 17 14 12

63.8 - 65.6 (25% of population) 26 27 27

Unrestrained 

> 65.6 (25% of population) 34 33 37

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).
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Male Drivers 

Restraint Use/Height (in) (#) 1998 2003 2004 

<= 67.3 (25% of population) 135 189 168

67.3 - 69.3 (25% of population) 143 183 226

69.3 - 71.3 (25% of population) 164 195 206

> 71.3 (25% of population) 208 251 298

Restrained 

Total 650 818 898

<= 67.3 (25% of population) 526 587 526

67.3 - 69.3 (25% of population) 652 715 690

69.3 - 71.3 (25% of population) 663 652 683

> 71.3 (25% of population) 806 775 782

Unrestrained 

Total 2,647 2,729 2,681

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Male Drivers 

Restraint Use/Height (in) (%) 1998 2003 2004 

<= 67.3 (25% of population) 21 23 19

67.3 - 69.3 (25% of population) 22 22 25

69.3 - 71.3 (25% of population) 25 24 23

Restrained 

> 71.3 (25% of population) 32 31 33

<= 67.3 (25% of population) 20 22 20

67.3 - 69.3 (25% of population) 25 26 26

69.3 - 71.3 (25% of population) 25 24 25

Unrestrained 

> 71.3 (25% of population) 30 28 29

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Body Mass Index. Body Mass Index is defined as follows. If weight is measured in kilograms 

and height in meters, it is the ratio of weight divided by height squared. If weight is measured in 

pounds and height in inches, then it is 703.07 times the ratio. 

2 2 ( )

( ) 703 07

( )

( )

height in

weight lbs . height mweight kg BMI = = . 

Among fatally injured drivers in single-vehicle rollovers, restrained fatalities tended to have a 

higher BMI than unrestrained fatalities. For example, according to Table 37, in 2004, 16% of the 

male restrained fatalities had a BMI of greater than 30.4, compared to 13% of the unrestrained 

male fatalities. Regardless of restraint use, drivers who were fatally injured tended to have a 

lower BMI than the general population. For example, in 2004, 39% of the female unrestrained 

drivers had a BMI of 23.1 or less, compared to 25% of such females in the general population. 
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72 

The male unrestrained drivers had the same tendency (28% vs. 24.8%). Finally, drivers with a 

higher BMI appeared to receive more benefits from wear 

Table 37 

Fatally injured drivers 20 years old or older in single-vehicle rollovers 

by sex, restraint use, and Body Mass Index, 1998, 2003, 2004 

Female Drivers 

Restraint Use/BMI (#) 1998 2003 2004 

<= 23.1 (25% of population) 118 143 140

23.1 - 26.8 (25% of population) 102 145 170

26.8 - 32 (25% of population) 42 56 66

> 32 (25% of population) 19 48 46

Restrained 

Total 281 392 422

<= 23.1 (25% of population) 333 305 311

23.1 - 26.8 (25% of population) 302 310 299

26.8 - 32 (25% of population) 92 115 106

> 32 (25% of population) 44 74 72

Unrestrained 

Total 771 804 788

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Female Drivers 

Restraint Use/BMI (%) 1998 2003 2004 

<= 23.1 (25% of population) 42 36 33

23.1 - 26.8 (25% of population) 36 37 40

26.8 - 32 (25% of population) 15 14 16

Restrained 

> 32 (25% of population) 7 12 11

<= 23.1 (25% of population) 43 38 39

23.1 - 26.8 (25% of population) 39 39 38

26.8 - 32 (25% of population) 12 14 13

Unrestrained 

> 32 (25% of population) 6 9 9

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).
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Male Drivers 

Restraint Use/BMI (#) 1998 2003 2004 

<= 24.2 (25% of population) 186 210 211

24.2 - 27.1 (25% of population) 292 376 385

27.1 - 30.4 (25% of population) 101 125 157

> 30.4 (25% of population) 71 107 145

Restrained 

Total 650 818 898

<= 24.2 (25% of population) 812 767 757

24.2 - 27.1 (25% of population) 1,147 1,173 1,111

27.1 - 30.4 (25% of population) 438 427 457

> 30.4 (25% of population) 250 362 356

Unrestrained 

Total 2,647 2,729 2,681

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Male Drivers 

Restraint Use/BMI (%) 1998 2003 2004 

<= 24.2 (25% of population) 29 26 23

24.2 - 27.1 (25% of population) 45 46 43

27.1 - 30.4 (25% of population) 16 15 17

Restrained 

> 30.4 (25% of population) 11 13 16

<= 24.2 (25% of population) 31 28 28

24.2 - 27.1 (25% of population) 43 43 41

27.1 - 30.4 (25% of population) 17 16 17

Unrestrained 

> 30.4 (25% of population) 9 13 13

Source: NHTSA, NCSA, FARS, 1998, 2003, 2004; McDowell et al. (2005).

Discussion. One finding of this section is that among fatally injured drivers, those who were 

restrained tended to weigh more, be taller, and have a higher BMI than those who were 

unrestrained. Another interesting finding is that drivers who weighed less, were taller, and had a 

lower BMI tended to be overrepresented in single-vehicle fatal rollovers. Thus, while heavier 

individuals received fewer benefits from seat belts, they might also have been at a lower risk of 

fatality given involvement in a single-vehicle rollover. On the other hand, this overrepresentation 

of lighter, taller, and lower BMI drivers could be related to age and its relationship to risk-taking. 
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Fatalities by State 

Table 38 shows the number of fatally injured passenger vehicle occupants by State. The first part 

of the table shows fatality counts for occupants in single-vehicle rollovers, occupants in all 

rollovers, and passenger vehicle occupants in all crashes. The second part of the table shows the 

amount of single-vehicle rollover occupant fatalities as a percent of all rollover occupant 

fatalities and the amount of all rollover occupant fatalities as a percent of all occupant fatalities. 

The row marked “USA” shows the quantities pooled for the 50 States plus the District of 

Columbia, but excluding Puerto Rico. The rows marked “Average,” “Standard Deviation,” 

“Minimum,” and “Maximum” show these summary statistics taken, again, over all the 50 States 

plus the District of Columbia. Thus, for example, in 2004, in the United States 33% of all 

passenger vehicle occupant fatalities were rollover fatalities. However, the average of this 

percentage across the States was 35%. 

In 2004, the States with the highest amounts of single-vehicle rollover fatalities as a percentage 

of all rollover fatalities were Mississippi (at 99%), North Dakota (94%), and Montana (92%). 

The States with the lowest percents of single-vehicle rollover fatalities as compared to all 

rollover fatalities were the District of Columbia (50%), Hawaii (63%), and New Jersey (68%). 

The States with the highest amount of rollover occupant fatalities as a percent of all occupant 

fatalities were Montana (67%), Wyoming (66%), and Idaho (56%). The States with the lowest 

percents were the District of Columbia (10%), Puerto Rico (12%), and New Jersey and 

Mississippi (18% each). 

Table 38 

Fatally injured occupants of passenger vehicles 

in single-vehicle rollovers, in all rollovers, and in all crashes 

by State (plus Puerto Rico), 1994, 2003, 2004 

1994 2003 2004 

Occupant 

fatalities Singlevehicle 

rollover 

Rollover All 

Singlevehicle 

rollover 

Rollover All 

Singlevehicle 

rollover 

Rollover All 

Alabama 215 250 921 230 285 836 282 343 951

Alaska 28 28 61 23 24 64 25 29 69

Arizona 205 253 622 289 377 800 344 415 797

Arkansas 119 149 506 170 196 513 156 187 565

California 766 982 2,869 841 1,086 2,937 850 1,068 2,786

Colorado 185 230 465 180 228 497 185 228 492

Connecticut 38 48 204 49 63 222 41 58 193

Delaware 15 19 82 24 31 110 20 25 104

Dist of Columbia 10 12 41 1 3 41 1 2 21

Florida 261 380 1,812 458 582 2,105 459 627 2,080

(Continued on Next Page) 
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1994 2003 2004 

Occupant 

fatalities Singlevehicle 

rollover 

Rollover All 

Singlevehicle 

rollover 

Rollover All 

Singlevehicle 

rollover 

Rollover All 

Georgia 236 290 1,147 275 356 1,247 316 397 1,279

Hawaii 20 26 62 20 22 84 19 30 82

Idaho 92 101 217 110 123 244 102 114 205

Illinois 235 308 1,118 254 309 1,063 216 273 985

Indiana 156 186 775 99 121 644 145 164 712

Iowa 102 113 399 105 112 349 81 92 305

Kansas 110 118 376 144 168 392 112 147 390

Kentucky 161 189 667 172 203 760 203 245 793

Louisiana 162 213 661 201 254 714 165 202 705

Maine 38 43 143 45 46 168 51 61 152

Maryland 64 75 468 61 80 456 83 113 450

Massachusetts 49 64 305 63 74 324 63 82 309

Michigan 175 239 1,092 172 219 960 145 185 875

Minnesota 126 150 518 166 215 520 129 157 452

Mississippi 97 98 662 124 128 764 139 141 778

Missouri 267 322 925 331 391 994 321 396 948

Montana 88 93 164 125 143 228 115 125 186

Nebraska 53 74 231 77 95 250 72 88 214

Nevada 101 116 206 108 126 255 109 131 262

New Hampshire 26 30 91 25 27 91 32 37 123

New Jersey 71 98 530 56 76 510 56 82 451

New Mexico 169 189 331 175 200 325 169 210 396

New York 167 218 1,094 164 194 923 165 200 948

North Carolina 246 318 1,127 309 395 1,230 315 395 1,185

North Dakota 28 35 75 30 36 82 34 36 82

Ohio 144 200 1,077 185 255 988 201 263 981

Oklahoma 182 229 579 167 206 549 186 238 602

Oregon 120 145 373 124 137 399 93 110 343

Pennsylvania 184 234 1,090 242 294 1,169 231 279 1,110

Rhode Island 7 11 36 16 17 74 19 21 65

South Carolina 128 152 639 223 250 763 250 295 826

South Dakota 53 56 106 91 95 169 67 79 155

Tennessee 251 312 1,018 261 310 966 315 378 1,067

Texas 616 721 2,476 795 1,002 2,893 695 876 2,707

Utah 116 117 263 108 121 241 105 121 218

Vermont 21 22 66 12 14 55 18 25 76

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1994 2003 2004 

Occupant 

fatalities Singlevehicle 

rollover 

Rollover All 

Singlevehicle 

rollover 

Rollover All 

Singlevehicle 

rollover 

Rollover All 

Virginia 214 243 739 163 192 763 166 201 730

Washington 132 157 489 122 154 445 124 144 414

West Virginia 83 95 288 74 88 313 103 114 324

Wisconsin 129 145 571 196 245 653 194 238 620

Wyoming 80 85 124 74 74 129 78 86 130

USA 7,341 8,981 30,901 8,529 10,442 32,271 8,565 10,553 31,693

Puerto Rico 26 33 333 32 36 266 26 30 249

Source: NHTSA, NCSA, FARS, 1994, 2003, 2004. 

Single-vehicle rollover fatalities as 

percent of all rollover fatalities 

Rollover fatalities as percent of all 

occupant fatalities 

1994 2003 2004 1994 2003 2004 

Alabama 86 81 82 27 34 36

Alaska 100 96 86 46 38 42

Arizona 81 77 83 41 47 52

Arkansas 80 87 83 29 38 33

California 78 77 80 34 37 38

Colorado 80 79 81 49 46 46

Connecticut 79 78 71 24 28 30

Delaware 79 77 80 23 28 24

Dist of Columbia 83 33 50 29 7 10

Florida 69 79 73 21 28 30

Georgia 81 77 80 25 29 31

Hawaii 77 91 63 42 26 37

Idaho 91 89 89 47 50 56

Illinois 76 82 79 28 29 28

Indiana 84 82 88 24 19 23

Iowa 90 94 88 28 32 30

Kansas 93 86 76 31 43 38

Kentucky 85 85 83 28 27 31

Louisiana 76 79 82 32 36 29

Maine 88 98 84 30 27 40

Maryland 85 76 73 16 18 25

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Single-vehicle rollover fatalities as 

percent of all rollover fatalities 

Rollover fatalities as percent of all 

fatalities 

1994 2003 2004 1994 2003 2004 

Massachusetts 77 85 77 21 23 27

Michigan 73 79 78 22 23 21

Minnesota 84 77 82 29 41 35

Mississippi 99 97 99 15 17 18

Missouri 83 85 81 35 39 42

Montana 95 87 92 57 63 67

Nebraska 72 81 82 32 38 41

Nevada 87 86 83 56 49 50

New Hampshire 87 93 86 33 30 30

New Jersey 72 74 68 18 15 18

New Mexico 89 88 80 57 62 53

New York 77 85 83 20 21 21

North Carolina 77 78 80 28 32 33

North Dakota 80 83 94 47 44 44

Ohio 72 73 76 19 26 27

Oklahoma 79 81 78 40 38 40

Oregon 83 91 85 39 34 32

Pennsylvania 79 82 83 21 25 25

Rhode Island 64 94 90 31 23 32

South Carolina 84 89 85 24 33 36

South Dakota 95 96 85 53 56 51

Tennessee 80 84 83 31 32 35

Texas 85 79 79 29 35 32

Utah 99 89 87 44 50 56

Vermont 95 86 72 33 25 33

Virginia 88 85 83 33 25 28

Washington 84 79 86 32 35 35

West Virginia 87 84 90 33 28 35

Wisconsin 89 80 82 25 38 38

Wyoming 94 100 91 69 57 66

USA 82 82 81 29 32 33

Average 83 83 81 33 34 35

Standard Deviation 8 10 8 12 12 12

Minimum 64 33 50 15 7 10

Maximum 100 100 99 69 63 67

Puerto Rico 79 89 87 10 14 12

Source: NHTSA, NCSA, FARS, 1994, 2003, 2004. 
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8. Logistic Analysis 

Rollover propensity 

In this subsection, we model the probability that a passenger vehicle rolls over given that it is in 

a single-vehicle crash. The dependent variable is a categorical variable that indicates whether a 

vehicle had rolled over. We consider all the passenger vehicles (all passenger cars and light 

trucks) that were in single-vehicle crashes between 2000 and 2004, inclusive, and that had a 

driver at the time of the crash. All the data are from the GES database. We consider the 

following explanatory variables: 

Categorical variables: vehicle type, driver restraint use, driver sex, alcohol involvement, 

vehicle maneuver prior to critical event, corrective action attempted, road type, and whether the 

crash was speed-related. 

Interval variables: driver age, speed limit, vehicle occupancy, and vehicle age. 

One interpretation of the driver restraint use variable is that it is a proxy for driver behavior in 

relation to traffic safety. It is possible that drivers who chose not to wear seat belts also chose to 

drive unsafely, which in turn could have lead to a higher probability that their vehicle rolled over 

given that it was involved in a crash. The results of the regression are consistent with such an 

interpretation. As Table 39 shows, the odds ratio of a single-vehicle crash being a rollover for 

unrestrained drivers as compared to restrained drivers was significantly greater than 1, indicating 

that unrestrained drivers did indeed have a higher probability of being in vehicles that rolled over 

in single-vehicle crashes than did restrained drivers. As not wearing a seat belt was a symptom of 

unsafe driving, simply having forced an otherwise unsafe driver to wear a seat belt might not 

have changed the probability of rollover for that driver. 

Whether alcohol was involved in the crash was derived from police-reported alcohol 

involvement. If any driver, pedestrian, cyclist, or other nonmotorist who was involved in a crash 

used alcohol, the crash was classified as having alcohol involvement. Note that simply because a 

crash had alcohol involvement does not mean that alcohol use caused the crash. Nevertheless, as 

the results of the logistic analysis show in Table 39, all other things being equal, if there was 

alcohol involvement, or if alcohol involvement was unknown, the odds of a vehicle rolling over 

were higher than if there was no alcohol involvement. 

Vehicle occupancy is the number of occupants that were present in the vehicle at the time of the 

crash. 

Table 39 shows results of the logistic analysis. For categorical variables, results are presented as 

odds ratios of the odds that the vehicle rolled over for the given category divided by the odds that 

it rolled over for the reference category. Recall that the odds of an event is the probability that 

the event occurs divided by the probability that it does not occur; see the Appendix for a further 

discussion. For example, all other things being equal, the odds that a sport utility vehicle rolled 

over are 3.60 times the odds that a passenger car rolled over. 
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79 

For interval scale variables, estimated coefficients are shown. A coefficient is the approximate 

percent change in the odds of rollover for a unit increase in the explanatory variable, provided 

that none of the other explanatory variables change. Thus, for example, all other things being 

equal, every additional vehicle occupant increased the odds of rollover by about 10.5%. 

The confidence intervals shown in the table were generated by the SAS software. The p-values 

for all the explanatory variables presented in the table are well below 1%. The only exception is 

Driver Sex, the p-value for which is 15%, which means that it is not statistically significant. Note 

that the variable has three categories – male, female, and unknown. The odds ratio of unknown 

versus male is not statistically significant, while the odds ratio of female versus male is, in fact, 

statistically significant. For this reason, we leave the Driver Sex variable in the model. 

Also note that for some categorical variables, the difference between two particular categories is 

not statistically significant. Nevertheless, the variables are overall statistically significant. One 

example of such a variable is “Driver restraint use” – there is no statistically significant 

difference between the “unknown” and “restrained” categories, however, the variable overall is, 

in fact, statistically significant. 

Table 39 

Logistic analysis of vehicle rollover given involvement in a single-vehicle crash, 2000-2004 

Estimate 95% Confidence Interval Parameter 

Odds Ratios 

Vehicle type Other Light Truck vs 

Passenger Car 1.85 1.39 2.46

 Pickup vs Passenger Car 1.95 1.80 2.11

 Sport Utility Vehicle vs 

Passenger Car 3.60 3.32 3.90

 Van vs Passenger Car 1.38 1.21 1.57

Driver restraint use Unknown vs Restrained 0.88 0.72 1.08

 Unrestrained vs Restrained 1.84 1.66 2.05

Driver sex Unknown vs Male 1.00 0.78 1.27

 Female vs Male 1.06 1.00 1.13

Alcohol involvement Unknown vs No 1.20 1.06 1.36

 Yes vs No 1.71 1.56 1.89

Maneuver prior to critical 

event Unknown vs Going Straight 0.53 0.38 0.74

 Changing Lanes vs Going 

Straight 1.23 1.03 1.47

 Negotiating a Curve vs Going 

Straight 1.88 1.70 2.08

 Other vs Going Straight 0.48 0.40 0.58

 Passing vs Going Straight 1.95 1.49 2.55

 Turning vs Going Straight 0.47 0.39 0.55

(Continued on Next Page) 
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Corrective action attempted Unknown vs None 1.33 1.18 1.51

 Braking vs None 1.16 0.97 1.40

 Other vs None 2.19 1.57 3.05

 Steering vs None 3.03 2.62 3.50

Road type Unknown vs Divided 

Highway 0.65 0.49 0.86

 One-way vs Divided Highway 0.84 0.72 0.99

 Undivided Two-Way vs 

Divided Highway 1.24 1.03 1.47

Speed-related Unknown vs No 1.20 1.01 1.43

 Yes vs No 2.31 2.04 2.62

 Coefficients 

Driver age (years) -0.015 -0.017 -0.012

Speed limit (mph) 0.040 0.033 0.047

Vehicle occupancy (persons) 0.105 0.068 0.143

Vehicle age (years) 0.017 0.012 0.022

Source: NHTSA, NCSA, GES, 2000-2004 

Kindelberger and Eigen (2003) modeled rollover of SUVs in crashes as a function of driver age, 

driver sex, and vehicle age. They found a negative relationship between probability of rollover 

and driver age, as did we. They found a positive and statistically significant relationship between 

the driver being male, as opposed to female, and probability of rollover. We found the opposite 

relationship. Finally, the paper found that, other things being equal, a one-year increase in 

vehicle age increased the odds of rollover by 3%. We found the increase in odds to be 1.7%. 

Subramanian (2005) used NHTSA’s State Data System (SDS) database to model rollover of 

passenger vehicles in single-vehicle crashes as a function of vehicle occupancy, speed limit, and 

a number of other variables. It found that, other things being equal, the addition of a single 

occupant increased the odds of rollover by a value between 6% (for passenger cars) and 19% (for 

sport utility vehicles). We found the increase across all vehicle types to be 11%. The paper also 

found that high speed limit is statistically significant and was correlated with a higher probability 

of rollover, as did we. 

Qualitatively, the results of the multivariate analysis tell basically the same story as the tables 

presented earlier in the Rollover Propensity section. For example, Table 8 shows that rollover 

rate increased with increasing vehicle age. This is confirmed by the positive Vehicle Age 

coefficient in Table 39. 

One important exception to this is the road type. Table 19 considers three types of roads: divided 

highway, undivided two-way street, and one-way street. The table indicates that single-vehicle 

crashes that occurred on divided highways had the highest rollover rate. It also shows that for 

light trucks, single-vehicle crashes on one-way streets had a higher rollover rate than crashes on 

undivided two-way streets. The multivariate analysis tells a different story. According to the 

logistic table, crashes that occurred on undivided two-way streets had the highest rollover rate, 
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followed by divided highways, then one-way streets, and then streets of unknown type, in that 

order. 

Results differ between the simple tabulation and the multivariate analysis for the following 

reason. Multivariate analysis considers the impact of each variable given that all the other 

explanatory variables in the analysis remain constant. In this particular case, it compares 

different road types at a fixed speed limit. In other words, the multivariate analysis says that if all 

road types had the same speed limit, then undivided two-way streets would have had the highest 

rollover propensity. The simple tabulation, on the other hand, reports past rollover incidence 

without controlling for other potentially confounding variables. One possible reason that divided 

highway had the highest rollover incidence is that divided highways tend to have higher speed 

limits and, as we see from both the tabulation and the multivariate analysis, higher speed limit is 

associated with a higher rollover rate. 

Injury Outcomes 

In this subsection, we model the probability that a passenger vehicle occupant was fatally injured 

given involvement in a single-vehicle rollover. The dependent variable is a categorical variable 

that indicates whether or not a vehicle occupant was fatally injured. We consider all the 

occupants of passenger vehicles that were involved in single-vehicle rollovers between 2000 and 

2004, inclusive. The data are from a combination of the FARS and the GES databases. 

Specifically, the data on occupants who were fatally injured is from the FARS database, while 

the data on occupants who were not fatally injured is from the GES database. We consider the 

following explanatory variables: 

Categorical variables: vehicle type, ejection status, restraint use, occupant sex, maneuver prior 

to critical event, corrective action attempted, road type, and whether the crash was speed-related. 

Interval variables: occupant age, vehicle age, speed limit, and vehicle occupancy. 

Ejection status indicates whether the occupant was totally ejected. 

We follow Lindsey (2006) in defining the speed-related variable for the observations taken from 

the FARS database. In particular, we consider the crash to have been speed-related if the driver 

in the crash either (a) had a speeding-related driver-related factor; or (b) had a speeding-related 

violation charged. 

When the regression was performed with all of the above explanatory variables, the speedrelated variable had a p-value of 57% and the vehicle age variable had a p-value of 19%, 

indicating that these variables are not statistically significant. Because we had no strong a priori

basis for thinking that these variables belong in the model, we removed them from the model. In 

the resultant model, maneuver prior to critical event has a p-value of 3%; all other explanatory 

variables have a p-value that is well below 1%. 
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Table 40 shows results of the logistic regression analysis. As before, for categorical variables, 

odds ratios are given. For example, all other things being equal, the odds of fatality were 10.53 

times higher if an occupant was totally ejected than if he was not ejected or not totally ejected. 

For interval variables, coefficients are given. For example, all other things being equal, an 

increase in the speed limit by 1 mile per hour increased the odds of fatality in single-vehicle 

rollovers by about 2.0%. 

Table 40 

Logistic analysis of occupant fatality given involvement in a single-vehicle rollover, 

2000-2004 

Estimate 95% Confidence 

Parameter Interval 

Odds Ratios 

Vehicle type Other Light Truck vs Passenger Car 0.07 0.02 0.24

 Pickup vs Passenger Car 0.73 0.57 0.92

 Sport Utility Vehicle vs Passenger Car 0.72 0.60 0.87

 Van vs Passenger Car 0.64 0.44 0.94

Restraint use Unknown vs Restrained 2.86 2.02 4.03

 Unrestrained vs Restrained 7.18 5.93 8.69

Ejection status Unknown vs No or Partial Ejection 0.12 0.07 0.22

 Total Ejection vs No or Partial Ejection 10.53 8.10 13.69

Sex Unknown vs Male 0.00 0.00 0.01

 Female vs Male 0.79 0.70 0.89

Maneuver prior to critical 

event Unknown vs Going Straight 0.92 0.35 2.48

 Changing Lanes vs Going Straight 1.19 0.77 1.84

 Negotiating a Curve vs Going Straight 0.93 0.73 1.18

 Other vs Going Straight 1.92 1.16 3.19

 Passing vs Going Straight 1.14 0.73 1.79

 Turning vs Going Straight 0.34 0.15 0.74

Corrective action attempted Unknown vs None 0.00 0.00 0.00

 Braking vs None 0.38 0.29 0.50

 Other vs None 13.20 9.19 18.97

 Steering vs None 0.26 0.22 0.32

Road type Unknown vs Divided Highway 0.25 0.16 0.38

 One-way vs Divided Highway 0.13 0.07 0.26

 Undivided Two-Way vs Divided Highway 1.31 1.00 1.71

Coefficients 

Occupant age (years) 0.034 0.030 0.038

Speed limit (mph) 0.020 0.008 0.032

Vehicle occupancy (persons) -0.098 -0.162 -0.033

Source: NHTSA, NCSA, FARS, GES, 2000-2004 

Note that for some variables, for unknown categories, the estimated odds ratios are zero or very 

close to it. For example, for unknown as opposed to male occupant sex, the estimated odds ratio 
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of fatality is 0.003 (shown as 0.00 in the table); for unknown as opposed to no corrective action 

attempted, the odds ratio of fatality is estimated to be very close to 0. These estimates are very 

curious since an odds ratio of zero means that the probability of fatality is also zero. Here is the 

explanation for why these estimates are zero. The variables in question are never or very rarely 

coded as unknown for fatalities but are coded as unknown with some frequency for non-fatally 

injured occupants. This could be because of differences in data collection procedures applied to 

fatalities as opposed to non-fatally injured occupants. Recall that in this report, data on fatalities 

comes from the FARS database, while data on other occupants comes from the GES database. So 

this difference in coding could reflect a difference in procedures between the two databases. In 

any event, because of the difference in coding, when the value of the variable is unknown, that is 

an almost sure indication that the observation is on a non-fatally injured occupant. This results in 

an estimate of the odds ratio of zero or very close to zero. 

Treacy et al. (2002) modeled injury outcomes in single-vehicle rollovers that occurred in 1996 

and 1997 in a particular area of Australia. Rather than modeling the probability of fatality, as we 

did, Treacy et al. modeled the probability of “major injury.” They found a positive relationship 

between the probability of “major injury” and total ejection, not wearing a seat belt, and a high 

vehicle speed. We likewise found a positive relationship between the probability of fatality and 

total ejection, not wearing a seat belt, and a high speed limit. 

Khattak et al. (2003) modeled injury outcomes of occupants of large trucks that rolled over in 

single-vehicles crashes in North Carolina from 1996 to 1998. Note that we modeled injury 

outcomes of passenger vehicle occupants rather than large truck occupants. They used ordered 

probit to model all injury outcomes possible on the KABCO scale. They found a positive 

relationship between injury severity and travel speed; we found a positive relationship between 

the probability of fatality and a high speed limit. However, they found that increased vehicle 

occupancy increased the probability of higher injury severity, whereas we found that it 

decreases it. 

Qualitatively, the results of the multivariate analysis are consistent with the tables presented 

earlier in the Injury Outcomes section. For example, Table 26 shows that unrestrained occupants 

were more likely to die in a single-vehicle rollover than restrained occupants. Multivariate 

analysis confirms this since in Table 40, the odds ratio for “Restraint Use: Unrestrained versus 

Restrained” is greater than 1. 

One exception to this is the vehicle type variable. According to Table 22, the probability of 

fatality given involvement in a single-vehicle rollover for passenger cars, pickups, and sport 

utility vehicles was about 3%; for vans, it was about 2%. In other words, according to the table, 

the probability was about the same for all four vehicle types. However, according to the results 

of the multivariate analysis shown in Table 40, the probability of fatality in a passenger car was 

significantly higher than the probability for each of the other vehicle types. 

Results differ between the simple tabulation and the multivariate analysis for the following 

reason. Multivariate analysis considers the impact of each explanatory variable given that all the 

other explanatory variables in the analysis remained constant. In this particular case, it compares 

the impact on probability of fatality of different vehicle types at a fixed ejection status, vehicle 
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occupancy, and so on. In other words, the multivariate analysis says that if the ejection status, 

vehicle occupancy, and the other explanatory variables did not change as the vehicle type 

changed, then passenger car occupants would have had the highest propensity to die given 

involvement in a single-vehicle rollover. The simple tabulation, on the other hand, reports 

fatality incidence without controlling for other potentially confounding variables. As Table 24 

shows, the probability of total ejection changed with vehicle type. Thus, ejection status might be 

one confounding factor. 

Discussion 

Considering the two logistic models above, we see that there are some factors that both increased 

the probability of a vehicle rolling over and increased the probability of occupant fatality given 

that the occupant was in a vehicle that rolled over, while other factors increased the probability 

of one while decreasing the probability of the other. For example, if a vehicle was turning as 

opposed to going straight immediately before the single-vehicle crash occurred, that decreased 

the probability that the vehicle rolled over (odds ratio is 0.47 < 1), and it also decreased the 

probability of occupant fatality if a rollover did occur (odds ratio is 0.34 < 1). The same is true 

for the speed limit. A higher speed limit was both correlated with an increased probability of 

rollover given involvement in a single-vehicle crash (coefficient is 0.04 > 0) and it was 

correlated with an increased probability of fatality given involvement in a single-vehicle rollover 

(coefficient is 0.02 > 0). 

On the other hand, all light trucks had a higher probability of rollover as compared to passenger 

cars (odds ratio for sport utility vehicles is 3.6 > 1), but being an occupant in a light truck 

decreased the probability of a fatal injury given a single-vehicle rollover (odds ratio for sport 

utility vehicles is 0.72 < 1). Similarly, higher vehicle occupancy increased the probability of 

rollover given involvement in a single-vehicle crash (coefficient is 0.11 > 0), but at the same 

time it decreased the probability of a fatality given involvement in a single-vehicle rollover 

(coefficient is -0.10 < 0). 

Appendix: Interpretation of Logistic Tables 

A logistic regression models the odds of a particular event as a function of explanatory variables. 

Let p be the probability than an event occurs before we observe whether or not the event has 

actually occurred. For example, this could be the probability that a vehicle rolls over given 

involvement in a crash, or the probability that an occupant is fatally injured given involvement in 

a rollover. Then 

p

p o − = 1

 is the odds of the same event. Table 41 shows the relationship 

between probabilities and odds. 
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Table 41 

Relationship between probabilities and odds. 

Probability Odds 

0.9 9.00 

0.8 4.00 

0.7 2.33 

0.6 1.50 

0.5 1.00 

0.4 0.67 

0.3 0.43 

0.2 0.25 

0.1 0.11 

Explanatory variables are of two types: categorical and interval. A categorical variable can take 

on two or more values that represent categories. An interval variable can take on any number of 

values that represent quantities. For categorical variables, the logistic regression tables give 

estimates of the odds ratios; for interval variables, the tables give estimates of the coefficients. 

An odds ratio describes the change in the odds of the event that is being modeled given a change 

in the categorical variable and given that none of the other explanatory variables that are present 

in the model change their values. A coefficient describes the change in the odds of the event 

given a small increase in the interval variable and given that none of the other explanatory 

variables that are present in the model change their values. For example, suppose we are 

modeling rollover given involvement in a single-vehicle crash (Table 39). The odds ratio 

“Vehicle Type: Pickup versus Passenger Car” describes the change in the odds of rollover given 

involvement in a single-vehicle crash given that the vehicle type was changed from a passenger 

car to a pickup and given that none of the other variables shown in the table changed their 

values. The coefficient “Driver Age (years)” describes the change in the odds of rollover given 

involvement in a single-vehicle crash given that the driver’s age increased by a small number of 

years and that none of the other variables shown in the table changed their values. 

If a categorical variable can represent C categories, then a logistic table gives C −1 odds ratios 

for it. The odds ratios are for C −1 categories relative to a particular category, called the 

reference category. For example, in Tables 39 and 40, Passenger Car is the reference category for 

the Vehicle Type variable. The odds ratio is the ratio of odds of the event being modeled given a 

particular category divided by the odds of the same event given the reference category. For 

example, in Table 39, the odds ratio “Vehicle Type: Pickup versus Passenger Car” is the odds of 

rollover given involvement in a single-vehicle crash given that the vehicle is a pickup divided by 

the odds of rollover given involvement in a single-vehicle crash given that the vehicle is a 

passenger car. Odds ratios greater than 1.0 indicate that the category was associated with a 

higher probability of the event relative to the reference category. Odds ratios of less than 1.0 

indicate the opposite, that the category was associated with a lower probability of the event 

relative to the reference category. For example, considering Table 39, the estimated odds ratio on 
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“Vehicle Type: Pickup versus Passenger Car” is 1.95, indicating that pickups had a higher 

probability of rollover given involvement in a single-vehicle crash than did passenger cars; the 

odds ratio on “Road Type: One-way versus Divided Highway” is 0.84, indicating that rollovers 

in single-vehicle crashes were less likely on one-way roads than they were on divided highways. 

The coefficients given for interval variables are the approximate percent changes in the odds of 

the event being modeled given a small increase in the interval variable. Positive coefficients 

indicate a positive relationship between the event being modeled and the explanatory variable; 

negative coefficients indicate a negative relationship. For example, in Table 39, the estimated 

coefficient for “Driver Age (years)” is -0.015. This means that as the driver age increased, the 

probability of rollover given involvement in a single-vehicle crash tended to decrease. More 

precisely, if driver age was increased by one year, the odds of rollover given involvement in a 

single-vehicle crash would be decreased by approximately 1.5%. 

9. Conclusion 

This report provides a general overview of the different factors related to passenger vehicle 

rollovers. It might prompt more detailed research into specific areas that are deemed to be 

interesting. For example, one potentially interesting area for further research is the effect of seat 

belts on injury outcomes as a function of occupant characteristics, such as body weight. Other 

potentially interesting areas for research would include investigating further the use of the driver 

restraint use variable as a proxy for driver safety and studying the relationship between rollover 

propensity observed in actual crashes and certain vehicle characteristics, such as the Static 

Stability Factor. 

The report uses both the FARS database and the NASS GES database. It could be extended with 

additional databases, such as the NASS CDS. CDS contains variables relevant to rollovers that 

are not present in either FARS or GES, such as the number of quarter turns that a vehicle has 

rolled over. Previous studies of rollovers, such as Eigen (2005), have used this database. 
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10. References 

Committee for the Study of a Motor Vehicle Rollover Rating System, “The National Highway 

Traffic Safety Administration’s Rating System for Rollover Resistance: An Assessment,” 

Transportation Research Board, The National Academies, 2002, Special Report 265. 

Dalrymple, G. D., “Logistic Regression Analysis SAS Runs of Risk Models Combining SSF and 

Dynamic Tests,” October 15, 2003, NHTSA-2001-9663. Washington, DC: National 

Highway Traffic Safety Administration. 

Deutermann, W. “Characteristics of Fatal Rollover Crashes” April 2002, DOT HS 809 438. 

Washington, DC: National Highway Traffic Safety Administration. 

Digges, K. H., & Eigen, A. M., “Crash Attributes That Influence the Severity of Rollover 

Crashes,” Proceedings of the 18th ESV Conference, No. 231, Nagoya, Japan. 2003. 

Eigen, A. M., “Rollover Crash Mechanisms and Injury Outcomes for Restrained Occupants.” 

July 2005, DOT HS 809 894. Washington, DC: National Highway Traffic Safety 

Administration. 

Glassbrenner, D., & Ye, J., “Seat Belt Use in 2006 ─ Overall Results,” November 2006, DOT 

HS 810 677. Washington, DC: National Highway Traffic Safety Administration. 

Griffin III, L.I., Davies, B.T., & Flowers, R. J., “Studying Passenger Vehicle Fires with Existing 

Databases,” January 2002, NHTSA-1998-3588-169. Washington, DC: National Highway 

Traffic Safety Administration. 

Haddon, W., “Options for the prevention of motor vehicle crash injury,” Israeli Medical Journal, 

1980, 16:45-65. 

Kindelberger, J., & Eigen, A.M., “Younger Drivers and Sport Sport utility Vehicles,” September 

2003, DOT HS 809 636. Washington, DC: National Highway Traffic Safety 

Administration. 

Khattak, A. J., Schneider, R. J., & Targa, F., “Risk factors in Large Truck Rollovers and Injury 

Severity: Analysis of Single-Vehicle Collisions,” Transportation Research Board 82nd

Annual Meeting, Paper number 03-2331, Washington, DC, January 2003. 

Le Breton, P., & Vervialle, F., “Studying Accident Severity by Multivariate Analysis of the 

French Register of Personal Injury Road Traffic Accidents: Restructuring the Multi-Level 

Accident Register,” Recherche Transports Sécurité, 2005, 86:17-41. 

Lindsey, T., “Fatality Analysis Reporting System (FARS) & National Automotive Sampling 

System General Estimates System (NASS GES) Analytical Data Classification Manual,” 

Revised February 24, 2006, draft. Washington, DC: National Highway Traffic Safety 

Administration. 

McDowell, M.A., Fryar, C.D., Hirsch, R., & Ogden, C, L., “Anthropometric Reference Data for 

Children and Adults: U.S. Population, 1999 – 2002,” National Center for Health 

Statistics, Advance Data from Vital and Health Statistics, Number 361, July 7, 2005. 

Morgan, C., “Effectiveness of Lap/Shoulder Belts in the Back Outboard Seating Positions,” June 

1999, DOT HS 808 945. Washington, DC: National Highway Traffic Safety 

Administration. 

NHTSA a, “National Automotive Sampling System Crashworthiness Data System 1994 -1996,” 

DOT HS 808 985, October 1999. Washington, DC: National Highway Traffic Safety 

Administration. 

NHTSA b, “Occupant Protection,” Traffic Safety Facts, 2004, DOT HS 809 909. Washington, 

DC: National Highway Traffic Safety Administration. 
 NHTSA’s National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590

88 

NHTSA c, “NASS GES Analytical User’s Manual 1988 – 2004,” 2004. Washington, DC: 

National Highway Traffic Safety Administration. [http://wwwnrd.nhtsa.dot.gov/Pubs/AUM04.PDF]. Retrieved March 28, 2007. 

NHTSA d, “Electronic 2004 FARS Coding and Validation Manual,” 2004. Washington, DC: 

National Highway Traffic Safety Administration. [http://wwwnrd.nhtsa.dot.gov/Pubs/FARS04CVMAN.PDF]. Retrieved March 28, 2007. 

NHTSA e, “Traffic Safety Facts 2004,” January 2006, DOT HS 809 919. Washington, DC: 

National Highway Traffic Safety Administration. 

Shelton, T. S. T. “Imputation in the NASS General Estimates System,” June 1993, DOT HS 807 

985. Washington, DC: National Highway Traffic Safety Administration. 

Strashny, A. “Annual Vehicle Safety Assessment Tables,” 2005. Washington, DC: National 

Highway Traffic Safety Administration. 

Subramanian, R. “Transitioning to Multiple Imputation – A New Method to Estimate Missing 

Blood Alcohol Concentration (BAC) values in FARS,” January 2002, DOT HS 809 403. 

Washington, DC: National Highway Traffic Safety Administration. 

Subramanian, R. “The Effect of Occupancy on the Rollover Propensity of Passenger Vehicles,” 

The 19th proceedings of the International Conference on the Enhanced Safety of Vehicles, 

Paper No. 05-0197, Washington, DC, June 2005. 

Tessmer, J.M. “FARS Analysis Reference Guide: 1975 to 2002,” 2002. Washington, DC: 

National Highway Traffic Safety Administration. 

Treacy, P.J., Jones, K., & Mansfield, C. “Flipped out of control: single-vehicle rollover accidents 

in the Northern Territory,” The Medical Journal of Australia, 176 (6): 260-263, 2002. 

Walz, M. C. “Trends in the Static Stability Factor of Passenger Cars, Light Trucks, and Vans,” 

June 2005, DOT HS 809 868. Washington, DC: National Highway Traffic Safety 

Administration. 

I thank Dennis Utter, Chou-Lin Chen, Joseph Tessmer, Rory Austin, Rajesh Subramanian, 

Nancy Bondy, Jim Simons, Ana María Eigen, Susan Partyka, Stephanie Binder, Marilouise 

Burgess, and many others for their help with this report. 

DOT HS 810 741

March 2007