DOT HS 811 882
`
`January 2014
`
`Updated Estimates of Fatality
`Reduction by Curtain and
`Side Air Bags in Side Impacts
`and Preliminary Analyses of
`Rollover Curtains
`
`IPR 2016-01790
`American Vehicular Sciences
`Exhibit 2018
`
`

`

`DISCLAIMER
`
`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 authors 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 or products are mentioned, it is 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.
`
`Suggested APA Format Citation:
`
`Kahane, C. J. (2014, January). Updated estimates of fatality reduction by
`curtain and side air bags in side impacts and preliminary analyses of rollover
`curtains. (Report No. DOT HS 811 882). Washington, DC: National Highway
`Traffic Safety Administration.
`
`

`

`Technical Report Documentation Page
`2. Government Accession No.
`
`3. Recipient’s Catalog No.
`
`5. Report Date
`January 2014 
`6. Performing Organization Code
`8. Performing Organization Report No.
`
`10.
`Work Unit No. (TRAIS)
`
`11. Contract or Grant No.
`
`13. Type of Report and Period Covered
`NHTSA Technical Report 
`14. Sponsoring Agency Code
`
`1. Report No.
`DOT HS 811 882  
`4. Title and Subtitle
`Updated Estimates of Fatality Reduction by Curtain and Side Air
`Bags in Side Impacts and Preliminary Analyses of Rollover Curtains
`7. Authors
`Charles J. Kahane, Ph.D.
`9. Performing Organization Name and Address
`Office of Vehicle Safety
`National Highway Traffic Safety Administration
`Washington, DC 20590 
`12. Sponsoring Agency Name and Address
`National Highway Traffic Safety Administration
`1200 New Jersey Avenue SE.
`Washington, DC 20590 
`15. Supplementary
`Notes
`
`16. Abstract
`Curtain and side air bags are designed to protect occupants in near-side impacts, those to the sides of vehicles
`adjacent to where the occupants are seated. Four major types of curtain and/or side air bags have been
`available in the United States since 1996. However, by model year 2011, 85 percent of new cars and LTVs
`(light trucks and vans) were equipped with curtains plus torso bags for drivers and right-front passengers.
`Curtains that deploy in rollover crashes began to appear in 2002; by 2011 about 45 percent of new cars and
`LTVs were equipped with such curtains. Logistic regression analyses of FARS data through calendar year
`2011 show statistically significant fatality reductions for all four types of curtain and side air bags in near-
`side impacts for drivers and right-front passengers of cars and LTVs:
`
`Fatality Reduction (%)
`
`Confidence Bounds
`
`
`
`Curtains plus torso bags
`Combination bag
`Curtain only
`Torso bag only
`
`Corresponding analyses of far-side impacts do not show corresponding, large benefits for curtain or side air
`bags. Curtains that deploy in rollover crashes show a statistically significant effect in first-event rollovers:
`The estimated fatality reduction is 41.3 percent (confidence bounds, 22.5 to 55.5%). Analyses should be
`repeated in about 3 or 4 years, when there will be considerably more data available.
`
`31.3
`24.8
`16.4
`7.8
`
`25.0 to 37.1
`17.7 to 31.2
`3.0 to 28.0
`.4 to 14.7
`
`17. Key Words
`FARS, occupant protection, fatality reduction, outcome
`evaluation, effectiveness, crashworthiness, side airbag,
`rollover sensor, ejection mitigation, curtains 
`19. Security Classif. (Of this report)
`20. Security Classif. (Of this page)
`Unclassified
`Unclassified
`Form DOT F 1700.7 (8-72)
`
`
`
`
`
`18. Distribution Statement
`Document is available to the public from the National
`Technical Information Service www.ntis.gov.
`
`22. Price
`
`21. No. of Pages
` 91
` Reproduction of completed page authorized
`
`
`
`
`
`i
`
`

`

`
`
`TABLE OF CONTENTS
`
`
`
`List of abbreviations .................................................................................................................... iii
`Executive summary ...................................................................................................................... iv
`
`1. Description, history, and previous studies of curtain and side air bags ............................... 1
`
`1.1 Curtain and side air bags designed to deploy in side impacts ..................................... 1
`
`1.2 Rollover curtains ......................................................................................................... 3
`
`1.3 Relevant FMVSS and consumer information programs ............................................. 4
`
`1.4
`Installation history ...................................................................................................... 5
`
`1.5 Previous studies .......................................................................................................... 8
`
`1.6 Analysis outline ........................................................................................................ 10
`
`2. Analyses of near-side impacts ........................................................................................... 11
`
`2.1 Logistic regression analyses for near-side impacts ................................................... 11
`
`
`2.1.1 General description ....................................................................................... 11
`
`
`
`2.1.2 FARS database .............................................................................................. 12
`
`
`
`2.1.3 The principal regression analysis for near-side impacts ............................... 16
`
`
`2.1.4 Alternative regression analyses ..................................................................... 22
`
`
`2.2 Contingency table analysis for curtain + torso bags in near-side impacts ................ 27
`
`2.3 FARS/GES analysis for curtain + torso bags in near-side impacts .......................... 29
`
`2.4 Conclusions: near-side impacts ................................................................................. 30
`
`3. Analyses of far-side impacts .............................................................................................. 30
`
`3.1 Logistic regression analyses for far-side impacts ..................................................... 32
`
`3.2 Contingency table analysis for curtain + torso bags in far-side impacts .................. 34
`
`3.3 FARS/GES analysis for curtain + torso bags in far-side impacts ............................. 35
`
`3.4 Discussion: far-side impacts ..................................................................................... 36
`
`4.
`
`
`
`
`
`
`
`
`
`Appendix A: Curtain and side air bags, by type, MY 1996-2011 .............................................. 51
`
`Appendix B: Make-models in the contingency-table and FARS-GES analyses ........................ 79
`
`Appendix C: Make-models in the contingency-table analyses of rollover curtains ................... 81
`
`Preliminary analyses of rollover curtains .......................................................................... 36
`4.1 Logistic regression analyses for first-event rollovers ............................................... 37
`4.2 Contingency table analyses for first-event rollovers ................................................ 41
`4.3 Analyses of fatal ejections in first-event rollovers ................................................... 43
`4.4 Analyses of subsequent-event rollovers that are not side impacts ............................ 44
`4.5 Analyses of rollover curtains in near-side impacts ................................................... 46
`4.6 Analyses of rollover curtains in far-side impacts ..................................................... 48
`4.7 Preliminary conclusions: rollover curtains ............................................................... 50
`
`
`
`ii
`
`

`

`
`
`
`
`
`
`AIS
`
`BMW
`
`CDS
`
`CUV
`
`CY
`
`DF
`
`ESC
`
`FARS
`
`GES
`
`IIHS
`
`LTV
`
`MDB
`
`MY
`
`NASS
`
`NCAP
`
`LIST OF ABBREVIATIONS
`
`Abbreviated Injury Scale
`
`Bayerische Motoren Werke
`
`Crashworthiness Data System of NASS
`
`crossover utility vehicle
`
`calendar year
`
`degrees of freedom
`
`electronic stability control
`
`Fatality Analysis Reporting System, a census of fatal crashes in the United
`States since 1975
`
`General Estimates System of NASS
`
`Insurance Institute for Highway Safety
`
`light trucks and vans; includes pickup trucks, CUVs, SUVs, minivans, and
`full-size vans
`
`moving deformable barrier
`
`model year
`
`National Automotive Sampling System, a probability sample of police-
`reported crashes in the United States since 1979, investigated in detail
`
`New Car Assessment Program: ratings of new vehicles since 1979 based on
`performance in frontal impact tests
`
`NHTSA
`
`National Highway Traffic Safety Administration
`
`RF
`
`SAS
`
`SUV
`
`TTI(d)
`
`VIN
`
`right-front seat
`
`statistical and database management software produced by SAS Institute, Inc.
`
`sport utility vehicle
`
`Thoracic Trauma Index measured on a dummy
`
`Vehicle Identification Number
`
`iii
`
`

`

`
`
`EXECUTIVE SUMMARY
`
`
`
`A curtain or side air bag is designed to protect an occupant’s head, torso, and/or pelvis in a side
`impact, specifically a “near-side” impact to the side of the vehicle adjacent to where the occupant
`is seated. While NHTSA has never explicitly required installation of curtain or side air bags, the
`agency encouraged it by listing, since 1996, the makes and models of vehicles that offer them in
`its Buying a Safer Car brochures and at www.safercar.gov; by expanding, in 1996, its NCAP
`consumer-information program to include star ratings for side impacts; and by upgrading, in
`2007, FMVSS No. 214, “Side impact protection,” adding an oblique 20 mph side impact test
`with a pole, with phase-in scheduled for MY 2011 to 2015. The agency anticipated that head-
`protection air bags would generally be installed to meet the new requirement.
`
`Several types of side air bags have been offered in the United States, including torso bags that
`deploy from the seat or door (first sold on 1996 Volvos), head curtains that deploy down from
`the roof-rail area (first sold as an inflatable tubular structure in MY 1998 BMWs), and
`combination bags that deploy outward from the seat and then quickly upward to provide torso as
`well as head protection. However, by 2006, the clear preference was for separate curtain and
`torso bags, the configuration that covers the largest area and intuitively appears to provide the
`most protection. In model year 2011, 85 percent of new cars and LTVs were equipped with
`curtains plus torso bags for drivers and right-front passengers.
`
`Meanwhile, some vehicles added rollover sensors that make it possible to also deploy the
`curtains in rollover crashes as well as side impacts (first sold on 2002 Ford Explorers and
`Mercury Mountaineers). In addition, recent curtains may cover a larger area and stay inflated
`longer to protect occupants in crashes with multiple impacts and to help prevent occupants’
`ejection from the vehicle in rollovers and other crashes. NHTSA anticipates curtains that deploy
`in rollovers will generally be used to meet FMVSS No. 226, “Ejection mitigation,” which is
`scheduled to phase in from MY 2014 to 2017. Installations are catching up with the other types
`of side air bags; in model year 2011, 45 percent of new cars and LTVs were equipped with
`curtains that deploy in rollovers.
`
`NHTSA issued a preliminary evaluation of side air bags in 2007, based on crash data through
`CY 2005 – before the widespread availability of separate curtain and torso bags. The analyses
`showed significant fatality reductions in near-side impacts for air bags offering head protection,
`but to do that the analyses had to merge curtain-plus-torso and combination bags into a single
`group with a single effectiveness estimate. NHTSA would now like to estimate the fatality
`reduction in near-side impacts specifically for curtain plus torso bags, as manufacturers are
`increasingly relying on this technology. Furthermore, the 2007 report had preliminary analyses,
`based on limited data, showing that curtain bags may be rather effective even for far-side
`occupants (e.g., the driver in a right-side impact); those analyses need to be revisited, as it is not
`intuitively clear why the technology would have a substantial effect in far-side impacts. The
`2007 report did not study curtains that deploy in rollover crashes.
`
`NHTSA’s Fatality Analysis Reporting System through 2011 now has enough crash data to
`estimate individually the fatality-reducing effectiveness of each of the major types of curtain or
`side air bags in near-side impacts – including over 10 times as much data on vehicles with
`
`
`
`iv
`
`

`

`
`
`curtains plus torso bags as in the 2007 report. A logistic regression, comprising 73,228 FARS
`cases, found statistically significant fatality reductions for each type of curtain or side air bags,
`for drivers and RF passengers.
`
`Estimated Fatality Reduction (%) in Near-Side Impacts, by Type of Side Air Bags
`
`
`Point Estimate
`
`Confidence Bounds
`
`
`
`Curtain plus torso
`Combination
`Curtain only
`Torso only
`
`31.3
`24.8
`16.4
`7.8
`
`25.0 to 37.1
`17.7 to 31.2
`3.0 to 28.0
`.4 to 14.7
`
`Separate curtain and torso bags show the highest effectiveness in near-side impacts: 31-percent
`fatality reduction, with relatively narrow confidence bounds from 25 to 37 percent.
`Supplementary contingency-table analyses of FARS and estimates of national fatality rates per
`1,000 occupants involved in near-side impacts, based on FARS and NASS-GES data, confirmed
`the logistic regression’s results for curtain plus torso bags. Effectiveness is approximately the
`same in cars and in LTVs, and for drivers and RF passengers.
`
`Analyses for far-side impacts did not show corresponding, large benefits for curtain plus torso
`bags. Although some of the regressions show positive, but relatively small effects, NHTSA does
`not believe there is, on the whole, enough evidence to quantify a specific fatality reduction in far-
`side impacts at this point. The analyses of far-side impacts should perhaps be repeated in about 3
`or 4 years, when there will be considerably more data available.
`
`FARS now also has enough data for initial statistical analyses of curtains that deploy in rollover
`crashes. Although the data is still limited, it shows these curtains save lives in first-event
`rollovers. The estimated fatality reduction is a statistically significant 41.3 percent, with
`confidence bounds ranging from 22.5 to 55.5 percent. These curtains help prevent occupant
`ejection and also mitigate injuries from contact with components and surfaces inside the vehicle:
`they are about equally effective in reducing ejection and non-ejection fatalities in first-event
`rollovers. With the existing data, NHTSA did not see a fatality reduction in subsequent-event
`rollovers and also could not determine if the recent curtains that deploy in rollovers are more
`beneficial than earlier curtain designs in near-side or far-side impacts. These analyses, too,
`should be repeated in about 3 or 4 years.
`
`
`
`v
`
`

`

`
`
`Description, history, and previous studies of curtain and side air bags
`1.
`1.1 Curtain and side air bags designed to deploy in side impacts
`Curtain and side air bags are designed to protect an occupant’s head, torso, and/or pelvis in a side
`impact, specifically a near-side impact to the side of the vehicle adjacent to where the occupant
`is seated. Some curtain air bags may also be designed to deploy in rollover crashes and/or to
`reduce an occupant’s risk of complete or partial ejection from the vehicle in crashes; they are
`discussed in the next section. The analyses of this report are limited to air bags for front-seat
`occupants, where NHTSA has enough data for statistically meaningful results. In this report, air
`bags designed to deploy in side impacts are grouped into four major categories:
`
`Torso air bags provide an energy-absorbing cushion between the occupant’s torso and the
`vehicle’s side structure during lateral impacts. They usually are built into the seat and deploy
`from there (Figure 1), but sometimes are built into the door (Figure 2). Some, but not all torso
`bags extend downward to also protect the pelvis (Figure 3).
`
`
`
`
`Figure 1
`Seat-Mounted Torso Bag
`
`Figure 2
`Door-Mounted Torso Bag
`
`Figure 3
`Torso Bag With Pelvis Protection
`
`
`
`
`
`
`
`Curtain air bags are built into the roof-rail area above the side window and deploy downward to
`cover the window area. They provide a cushion between the occupant’s head and some of the
`rigid surfaces of the vehicle interior, such as the roof rail, the window sill, the A-pillar, or the B-
`pillar. They might also prevent partial or complete ejection of the occupant through the side-
`window area and prevent direct occupant contact with the striking vehicle or object. Some early
`designs of curtain bags had a limited longitudinal span, leaving a substantial portion of the
`window uncovered (Figure 4) or were inflatable tubular structures with a limited vertical span
`(Figure 5).
`
`
`
`1
`
`

`

`
`
`
`
`
`
`Figure 4: Curtain Air Bag (Narrow Span)
`
`Figure 5: Inflatable Tube
`
`
`
`
`
`Many recent curtains cover a wide longitudinal and vertical span, including most of the side-
`window area and the harder structures around it (Figure 6).
`
`Combination bags are torso bags that deploy outward from the seat and then quickly upward to
`also provide head protection (Figure 7). Unlike curtains, they cover a somewhat limited area
`immediately to the occupant’s side. Intuitively, they might not have as much effect as curtain air
`bags in preventing ejection or in an oblique lateral impact, i.e., if the occupant’s trajectory is
`toward the front of the window area, which is not covered by the air bag. Shortly after 2000, a
`variety of models offered combination bags, but by the end of the decade they were limited
`primarily to convertibles, where there is no roof rail for installing a curtain air bag.
`
`
`
`Figure 6: Curtain Air Bag (Wide Span)
`
`Figure 7: Combination Bag
`
`
`
`2
`
`
`
`

`

`
`
`Curtain plus torso bags provide the most extensive side-impact protection. The curtains are
`separate from the torso bags, although they usually share components such as sensors and the
`control module (Figure 8). Recently, suppliers have developed a head-impact air bag for use in
`convertibles; it covers an area similar to a curtain, but deploys up from the door rather than down
`from the roof rail (Figure 9). Vehicles equipped with separate head-impact bags and torso bags
`are included with curtain plus torso bags in this report.
`
`
`
`
`Figure 8
`Curtain Plus Torso Bags
`
`Figure 9
`Door-Mounted Head-Impact Air Bag
`
`
`
`1.2 Rollover curtains
`Equipping a vehicle with a rollover sensor makes it possible to deploy the curtains in a first-
`event rollover and even in a post-impact rollover if the vehicle’s electrical system is still
`functional after the initial impact. In addition, many recent curtains (often, but not necessarily
`always rollover curtains) may cover a larger area, horizontally and vertically than some earlier
`designs to protect occupants from contacts with a wider range of components and possibly to
`enhance performance in an oblique pole impact and/or an occupant containment test. Figures 4
`and 5, for example, illustrate early curtain or tube designs covering a limited area, whereas the
`curtains in Figures 6 and 8 appear to cover the entire window and the rigid structures around the
`window.1 A third feature of rollover curtains is that they remain inflated for some time after
`initial deployment – e.g., six seconds or more – to protect occupants in prolonged rollover
`events2, cases with complex trajectories, or multiple crash events. The combination of rollover
`sensors, larger curtains, and prolonged inflation ought to reduce an occupant’s risk of complete
`or partial ejection from the vehicle in rollover crashes – but it might also help prevent ejection in
`side impacts that are not rollovers and/or reduce injury risk from interior contacts in rollovers
`and side impacts.
`
`1 The curtain in Figure 8, although covering a large area, is not in a vehicle with rollover sensors.
`2 Investigations of vehicles without curtain air bags in rollover crashes that transverse long distances and many
`quarter turns often find that \ unbelted occupants were ejected at the end of the rollover sequences, \ thus, the need
`for rollover curtains to remain inflated for six seconds or more.
`
`
`
`3
`
`

`

`
`
`In theory, analyses could consider six categories of air bags – torso only, combination, non-
`rollover curtain only, rollover curtain only, non-rollover curtain plus torso, and rollover curtain
`plus torso – rather than just the four defined in Section 1.1. However, at the time of writing this
`report, the small numbers of cases with rollover curtains (with or without torso bags) and their
`concentration among certain vehicle types precludes that approach, as will be discussed in
`Section 1.6.
`
`1.3 Relevant FMVSS and consumer information programs
`No safety standard explicitly requires vehicles to have curtain or side air bags, but several
`FMVSS and a consumer-information program have implicitly prompted or encouraged their
`installation. NHTSA upgraded FMVSS No. 214, “Side impact protection,” in 1990 with a phase-
`in scheduled for MY 1994 to 1997, to include a crash test in which a moving deformable barrier
`strikes the vehicle in the side. An injury criterion, the thoracic trauma index, is measured on a
`dummy seated near the impact location. Initially, manufacturers added structure or padding in or
`around the door to obtain TTI(d) scores low enough to meet the new standard. In late 1996,
`however, NHTSA expanded its New Car Assessment Program to include side impacts at speeds
`5 mph faster than the test in FMVSS No. 214. Since torso air bags tend to substantially improve
`TTI(d) scores, the publication of NCAP star ratings for side impacts based to a large extent on
`TTI(d) may have been an incentive to expedite the introduction of torso bags in vehicles.3
`
`NHTSA upgraded FMVSS No. 201, “Occupant protection in interior impact,” in 1995, with a
`phase-in scheduled for MY 1999 to 2003, to reduce the risk of head injury from contact with the
`A-, B- and other pillars, the front and rear roof header, the roof side rails, and the upper roof.4
`Many of these injuries were happening in side impacts. Initially, most manufacturers added
`energy-absorbing materials in the target areas to meet the standard, but curtain bags were
`evidently a potential strategy for further reduction of head injuries. In fact, NHTSA modified
`some of the test procedures of FMVSS No. 201 in 1998 to facilitate introduction of head
`curtains.5 The FMVSS No. 201 upgrade is a confounding effect in the analyses of this report,
`because injury reductions in side impacts due to the energy-absorbing materials pursuant to the
`upgrade should not be attributed to air bags.
`
`
`3 Kahane, C. J. (2007, January). An Evaluation of Side Impact Protection – FMVSS 214 TTI(d) Improvements and
`Side Air Bags. (Report No. DOT HS 810 748, pp. 11-29). Washington, DC: National Highway Traffic Safety
`Administration. Available at www-nrd.nhtsa.dot.gov/Pubs/810748.PDF; Federal Register 55 (October 30, 1990):
`45722.
`4 Kahane, C. J. (2011, November). Evaluation of the 1999-2003 Head Impact Upgrade of FMVSS No. 201 – Upper-
`Interior Components: Effectiveness of Energy-Absorbing Materials Without Head-Protection Air Bags. (Report No.
`DOT HS 811 538, pp. 1-17). Washington, DC: National Highway Traffic Safety Administration. Available at www-
`nrd.nhtsa.dot.gov/Pubs/811538.PDF; Federal Register 60 (August 18, 1995): 43031.
`5 Federal Register 63 (August 4, 1998): 41451; soon after curtain bags first became available on some cars, NHTSA
`amended FMVSS No. 201 to facilitate their introduction on other vehicles. Recognizing that the 15 mph headform
`test might be a problem in target areas where the undeployed air bag is stored (and, furthermore, an inappropriate
`test if the bag usually deploys at that speed), NHTSA offered an alternative compliance procedure. Manufacturers
`have the option to reduce the speed of the headform test to 12 mph on target areas where the bag is stored, provided
`they can also meet an 18 mph lateral (90-degree) crash test for the full vehicle into a pole – with HIC < 1,000. The
`pole test simulates a head impact with the deployed bag.
`
`
`
`4
`
`

`

`
`
`In 2007, the agency further upgraded FMVSS No. 214 by adding a crash test of a 20 mph side
`impact with a pole, at a 75-degree angle (i.e., 15 degrees forward of a purely lateral impact).6
`The phase-in is scheduled for MY 2011 to 2015. NHTSA anticipated that head-protection air
`bags – i.e., curtain bags if possible; combination bags or door-mounted head-impact bags in
`convertibles without a roof rail – would generally be installed to meet the new requirement,
`because they appeared to be the principal technology available for cushioning an occupant in
`oblique impacts.
`
`Finally, in 2011, NHTSA issued FMVSS No. 226, “Ejection mitigation,” with a phase-in
`scheduled for MY 2014 to 2017.7 The goal is to prevent the ejection of unrestrained occupants
`and the partial ejection of belted occupants in rollovers and other crashes. NHTSA anticipated
`that containment of the occupant would be achieved in many vehicles by a deployable ejection
`mitigation device – e.g., a curtain air bag that is designed to deploy in rollovers, stay inflated for
`six seconds, and be large enough to cover the window area and strong enough to contain the
`occupant. In other words, the new standard not only assumes many vehicles will have curtains or
`similar technology but is also likely influencing parameters such as the size of the curtains, when
`they deploy, and how long they stay inflated.
`
`Installation history
`1.4
`Table 1 and Figure 10 show how installations of curtain or side air bags have increased from 0.3
`percent of MY 1996 cars and LTVs involved in fatal crashes to almost 97 percent in MY 2011.
`The statistics are based on CY 1995 to 2011 FARS data and the VIN-decode programs derived
`from the information in Appendix A of this report. In other words, the statistics are for vehicles
`involved in fatal crashes and do not necessarily correspond to market shares. Volvo introduced
`torso bags in the United States, making them standard equipment on all their MY 1996 cars.
`Audi, BMW, and Cadillac began to furnish torso bags as standard equipment on some 1997
`models and offer them as options on others. The first LTVs with standard torso bags were the
`1998 Chevrolet Venture, Oldsmobile Silhouette, Pontiac Trans Sport vans and Mercedes SUVs.
`BMW introduced inflatable tubes for head protection, in combination with torso bags in their
`1998 500-series and 700-series cars. In 1999, Mercedes E-series and Volvo S-80 were equipped
`with curtains plus torso bags. Head curtains alone, without torso bags, did not appear until MY
`2001, as options in some Chrysler, Dodge, and Saturn cars. Combination bags were standard in
`1999 on Lincoln Town Car and Continental and Infiniti Q45, G20, and QX4; also optional on
`some other Ford Motors cars and LTVs. Rollover curtains first appeared in 2002, as optional
`equipment on Ford Explorer and Mercury Mountaineer. Rollover curtains with torso bags were
`standard on Mercedes S-, CL-, and E-series cars, Volvo XC90, and Lexus LX in 2003 and
`optional on Toyota Landcruisers.
`
`
`6 Federal Register 72 (September 11, 2007): 51908.
`7 Federal Register 76 (January 19, 2011): 3212.
`
`
`
`5
`
`

`

`
`
`
`
` Model
` Year
`
`1995
`1996
`1997
`1998
`1999
`2000
`2001
`2002
`2003
`2004
`2005
`2006
`2007
`2008
`2009
`2010
`2011
`
`Table 1: Percent of Vehicles Equipped With Side Air Bags, by Model Year
`(1995 to 2011 FARS data: vehicles involved in fatal crashes)
`
`
`No
`Air
`Bags
`
` 100.00
` 99.73
` 98.60
` 94.58
` 92.22
` 85.03
` 78.85
` 72.75
` 75.35
` 72.45
` 72.16
` 63.51
` 46.21
` 32.23
` 13.35
` 4.91
` 3.40
`
`Torso
`Bags
`Only
`
`none
` 0.27
` 1.40
` 5.19
` 5.43
` 9.70
` 10.06
` 14.99
` 9.98
` 8.33
` 4.08
` 2.51
` 0.60
` 0.32
` 0.31
` 0.05
`none
`
`
`
`Non-Roll
`
`Curtain Only
`
`Roll
`
`
`
`Total
`
`Combi-
`nation
`Bags
`
` Curtain Plus Torso
`
`
`Non-Roll
`Roll
`
`
`
`Total
`
`All
`Rollover
`Curtains
`
`none
`none
`none
`none
`none
`none
` 0.21
`1.06
` 1.11
`2.66
`3.06
`4.40
`8.04
`7.07
`6.58
`6.43
`4.45
`
`none
`none
`none
`none
`none
`none
`none
` 0.50
`1.09
` 1.11
` 1.29
` 1.66
` 7.01
` 8.17
` 6.44
` 4.12
`2.91
`
`none
`none
`none
`none
`none
`none
` 0.21
` 1.56
` 2.20
` 3.77
` 4.34
` 6.06
` 15.05
` 15.24
` 13.02
` 10.55
` 7.36
`
`none
`none
`none
`none
`1.78
`4.43
` 7.96
` 6.89
` 6.36
` 5.69
` 6.43
` 5.28
` 4.22
` 4.35
` 4.67
` 4.21
` 3.40
`
`none
`none
`none
` 0.23
` 0.57
` 0.84
` 2.92
` 3.81
` 5.78
` 8.84
` 10.09
` 16.82
` 25.96
` 35.10
` 52.99
` 49.10
` 43.85
`
`none
`none
`none
`none
`none
`none
`none
`none
` 0.33
` 0.91
` 2.89
` 5.83
` 7.95
` 12.76
` 15.65
` 31.18
`41.98
`
`none
`none
`none
` 0.23
` 0.57
` 0.84
` 2.92
` 3.81
`6.11
` 9.75
` 12.98
` 22.65
` 33.91
` 47.86
` 68.65
` 80.28
` 85.83
`
`none
`none
`none
`none
`none
`none
`none
`0.50
`1.42
` 2.02
` 4.18
` 7.49
`14.96
` 20.93
` 22.09
` 35.30
`44.89
`
`
`
`6
`
`

`

`
`
`
`
`
`
`Figure 10: Percentage of Vehicles With
`
`Side Air Bags, By Model Year
`
`
`
`100%
`
`90%
`
`80%
`
`70%
`
`60%
`
`50%
`
`40%
`
`30%
`
`20%
`
`10%
`
`0%
`
`LOKDNOOO'WcDx—INMVankDNOOO'WOx—I
`mmmmmoooooooooofifi
`mmmmmoooooooooooo
`HHHHHNNNNNNNNNNNN
`
`m rollover curtain+torso
`
`l nonrollovercurtain+torso
`
`combination
`
`E rollover curtain only
`
`nonrollovercurtain only
`
`ltorsoonly
`
`I none
`
`7
`
`

`

`
`
`The big story in Table 1 and Figure 10 is the growing market share of curtain plus torso bags,
`from less than 1 percent in MY 2000 to nearly 86 percent in MY 2011, with most of the growth
`from 2005 to 2010.
`
`Torso bags alone predominated in the early years, reaching a peak of 15 percent of MY 2002
`vehicles. Thereafter, shares decreased as manufacturers added curtains, replaced the torso bag
`with a combination bag, or reduced torso bags from standard to optional equipment.
`Combination bags’ highest share was 8 percent in 2001. At first, combination bags were
`available on a variety of convertibles, coupes, sedans, SUVs, CUVs, and minivans, but later they
`were increasingly limited to convertibles, where there is no roof rail to install curtains. In MY
`2011, the joint share for curtain-plus-torso and combination bags was 89 percent, meaning that
`almost 90 percent of the new-vehicle fleet had some kind of head and torso protection. Head
`curtains alone were fairly common after 2005, reaching 15 percent of new-vehicles sales in MY
`2007 and 2008, but then dropping back as manufacturers added torso bags. They were especially
`common in LTVs during those years.
`
`Introduction of rollover curtains (with or without torso bags) has lagged about three years behind
`the introduction of curtain plus torso bags, not exceeding 10 percent of new vehicles until MY
`2007. Rapid growth began in MY 2010, but that is too late to contribute large numbers of cases
`to the databases for this report (which go up to CY 2011). Furthermore, the trend to rollover
`curtains has been concentrated in CUVs and truck-based SUVs, slower in cars and pickup trucks.
`
`Previous studies
`1.5
`NHTSA’s 2007 evaluation report: The statistical analyses of side impacts in NHTSA’s 2007
`evaluation comprises FARS data on vehicles of MY 1994 (two years before the first side air
`bags) to 2003 in crashes of CY 1993 to 2005. The report does not address rollover curtains,
`which were just beginning to appear in those model years. A total of 1,503