U.S. Department
`of Transportation
`National Highway
`Traffic Safety
`Administration
`____________________________________________________________________________________________
`
`DOT HS 810 748
`NHTSA Technical Report
`
`January 2007
`
`An Evaluation of Side Impact Protection
`
`FMVSS 214 TTI(d) Improvements and Side Air Bags
`
`IPR 2016-01790
`American Vehicular Sciences
`Exhibit 2040
`____________________________________________________________________
`
`This document is available to the public at the Docket Management System of the U.S. Department of Transportation.
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`The United States Government does not endorse products or
`manufacturers. Trade or manufacturers’ names appear only
`because they are considered essential to the object of this report.
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`5. Report Date
`
`January 2007
`6. Performing Organization Code
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`8. Performing Organization Report No.
`
`10. Work Unit No. (TRAIS)
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`11. Contract or Grant No.
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`13. Type of Report and Period Covered
`
`NHTSA Technical Report
`14. Sponsoring Agency Code
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` Technical Report Documentation Page
`
`1. Report No.
`2. Government Accession No.
`3. Recipient’s Catalog No.
`
`DOT HS 810 748
`4. Title and Subtitle
`
`AN EVALUATION OF SIDE IMPACT PROTECTION
`
` FMVSS 214 TTI(d) Improvements and Side Air Bags
`
`7. Author(s)
`
`Charles J. Kahane, Ph.D.
`9. Performing Organization Name and Address
`
`Evaluation Division; National Center for Statistics and Analysis
`National Highway Traffic Safety Administration
`Washington, DC 20590
`12. Sponsoring Agency Name and Address
`
`Department of Transportation
`National Highway Traffic Safety Administration
`Washington, DC 20590
`15. Supplementary Notes
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`
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`16. Abstract
`
`Federal Motor Vehicle Safety Standard 214, “Side Impact Protection” was amended to assure occupant
`protection in a 33.5 mph crash test and phased-in to new passenger cars during model years 1994-1997.
`A Thoracic Trauma Index, TTI(d) is measured on Side Impact Dummies seated adjacent to the impact
`point. Manufacturers upgraded side structures and affixed padding in cars to improve TTI(d). Later, they
`installed two types of side air bags – torso bags and head air bags – for additional occupant protection in
`cars and LTVs. Statistical analyses of 1993-2005 crash data from the Fatality Analysis Reporting System
`(FARS) and the General Estimates System (GES) estimate fatality reductions for these technologies.
`• Average TTI(d) improved in 2-door cars from 114 in 1981-1985 to 44 in 214-certified cars with
`side air bags, and in 4-door cars from 85 to 48.
`• TTI(d) improvements without side air bags reduced fatality risk for nearside occupants in
`multivehicle crashes by an estimated 33 percent in 2-door cars and 17 percent in 4-door cars.
`• Torso plus head air bags reduce fatality risk for nearside occupants by an estimated 24 percent;
`torso bags alone, by 12 percent.
`• TTI(d) improvements, torso bags and head-curtain air bags could have saved an estimated 2,934
`lives in calendar year 2003 if every car and LTV on the road had been equipped with them.
`18. Distribution Statement
`7. Key Words
`
`Document is available to the public at the Docket
`Management System of the U.S. Department of
`Transportation, http://dms.dot.gov, Docket Number
`27588.
`20. Security Classif. (Of this page)
`
`Unclassified
`Reproduction of completed page authorized
`
`NHTSA; FARS; NASS; GES; FMVSS; statistical
`analysis; evaluation; benefits; effectiveness; fatality
`reduction; crashworthiness; angle collision
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`1
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`19. Security Classif. (Of this report)
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`Unclassified
`Form DOT F 1700.7 (8-72)
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`21. No. of Pages
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` 178
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`22. Price
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`TABLE OF CONTENTS
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`
`
`
`Acknowledgements.....................................................................................................................vii
`Executive summary......................................................................................................................ix
`
`1. Occupant protection in side impacts.................................................................................... 1
`
`1.1 The side impact problem in passenger cars ................................................................ 1
`
`1.2 Side door beams: an early measure to protect occupants ......................................... 10
`
`1.3 The dynamic test requirement for FMVSS 214........................................................ 11
`
`1.4 Technologies to protect occupants in side impacts................................................... 14
`
`1.5 What actually happened: average TTI(d), 1981-2002 .............................................. 17
`
`1.6 Summary of the Phase 1 evaluation report ............................................................... 30
`
`1.7 Braver-Kyrychenko and McCartt-Kyrychenko analyses of side air bags ................ 31
`
`1.8 Evaluation goals........................................................................................................ 32
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`2.
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`3.
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`Effect of side air bags on fatalities and ejection in side impacts ....................................... 69
`3.0 Summary................................................................................................................... 69
`3.1 Car models that received standard or optional side air bags..................................... 69
`3.2 Basic analyses of torso and head air bags in nearside impacts of cars ..................... 80
`3.3 Fatality reduction by torso air bags in nearside impacts........................................... 94
`3.4 Fatality reduction by torso bags plus head protection in nearside impacts............... 97
`3.5 Fatality reduction in farside impacts of passenger cars .......................................... 105
`3.6 Reduction of occupant ejection in side impacts...................................................... 117
`3.7 Fatality reduction by side air bags in LTVs: early results ...................................... 119
`3.8 Child passengers and side air bags.......................................................................... 120
`3.9 Vehicles with head curtains only: early results....................................................... 121
`3.10 Best effectiveness estimates.................................................................................... 123
`
`Effect of TTI(d) improvements on nearside fatalities in multivehicle crashes –
`after 1993, without side air bags........................................................................................ 35
`2.0 Summary................................................................................................................... 35
`2.1 A file of side impact test results for passenger cars.................................................. 35
`2.2 Make-models that substantially improved TTI(d) without side air bags.................. 37
`2.3 Fatalities per 1,000 nearside occupants in multivehicle side impacts ...................... 47
`2.4 Nearside fatalities in multivehicle crashes relative to non-occupant fatalities......... 59
`2.5 Analysis of compact pickup trucks........................................................................... 63
`2.6 Best effectiveness estimates for passenger cars........................................................ 65
`
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`iii
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`4.
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`Lives saved and savable in 2003 by side impact protection ............................................ 127
`4.0 Summary................................................................................................................. 127
`4.1 A model for estimating lives saved and savable by side impact protection ........... 127
`4.2 Parameters for the model ........................................................................................ 130
`4.3 Results..................................................................................................................... 135
`
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`References ................................................................................................................................. 141
`
`Appendix A: Make-model groups for evaluation of FMVSS 214........................................... 145
`
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`ABS
`
`AIS
`
`LIST OF ABBREVIATIONS
`
`Antilock brake system
`
`Abbreviated Injury Scale
`
`ANPRM
`
`Advance Notice of Proposed Rulemaking
`
`BMW
`
`Bayerische Motoren Werke
`
`CATMOD
`
`Categorical models procedure in SAS
`
`df
`
`DOT
`
`EU
`
`FARS
`
`Degrees of freedom
`
`United States Department of Transportation
`
`European Union
`
`Fatality Analysis Reporting System (a census of fatal crashes in the United States
`since 1975)
`
`FMH
`
`Free-motion headform
`
`FMVSS
`
`Federal Motor Vehicle Safety Standard
`
`GES
`
`GM
`
`GVWR
`
`HIC
`
`IIHS
`
`IR
`
`kph
`
`LTV
`
`MDB
`
`mph
`
`
`
`General Estimates System of NASS
`
`General Motors
`
`Gross Vehicle Weight Rating (specified by the manufacturer, equals the vehicle’s
`curb weight plus maximum recommended loading)
`
`Head Injury Criterion
`
`Insurance Institute for Highway Safety
`
`Information Request (from NHTSA)
`
`Kilometers per hour
`
`Light trucks and vans (includes pickup trucks, SUVs, minivans and full-sized
`vans)
`
`Moving deformable barrier
`
`Miles per hour
`
`v
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`

`
`
`msec
`
`MY
`
`NASS
`
`NCAP
`
`Milliseconds
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`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 (consumer information supplied by NHTSA on the
`safety of new cars and LTVs, based on test results, since 1979)
`
`NHTSA
`
`National Highway Traffic Safety Administration
`
`NICB
`
`NPRM
`
`NVPP
`
`PSU
`
`RF
`
`SAS
`
`SID
`
`SUV
`
`TTI
`
`National Insurance Crime Bureau
`
`Notice of Proposed Rulemaking
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`R.L. Polk’s National Vehicle Population Profile
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`Primary sampling unit
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`Right-front
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`Statistical analysis software produced by SAS Institute, Inc.
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`Side impact dummy
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`Sport utility vehicle
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`Thoracic Trauma Index
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`TTI(d)
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`Thoracic Trauma Index for the dummy in a side-impact test
`
`VIN
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`VMT
`
`Vehicle Identification Number
`
`Vehicle miles of travel
`
`
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`vi
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`

`ACKNOWLEDGEMENTS
`
` owe special thanks to the three researchers who peer-reviewed a draft of this report:
`
`
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`
`
` I
`
`1) Mr. Dainius J. Dalmotas, Chief, Crashworthiness Research, Motor Vehicle Standards and
`Research, Transport Canada (Retired), Gatineau, Quebec, Canada
`
`2) Mr. John L. Jacobus, Mechanical Engineer, National Highway Traffic Safety
`Administration (Retired), Silver Spring, MD
`
`
`
`
`
`3) Mr. Anders Lie, Vehicle Safety Specialist, Swedish National Road Administration,
`Borlange, Sweden
`
`
`This study estimates the fatality-reducing effectiveness of side air bags, based on statistical
`analyses of crash data. The National Highway Traffic Safety Administration (NHTSA) plans to
`use the statistical results when it estimates the benefits of a future final rule: the addition of a
`pole test to Federal Motor Vehicle Safety Standard (FMVSS) No. 214, Side Impact Protection.
`Because of the potential cost impacts of the proposed regulation, the report contains “highly
`influential scientific information” as defined by the Office of Management and Budget’s (OMB)
`“Final Information Quality Bulletin for Peer Review” (available at
`www.whitehouse.gov/omb/inforeg/peer2004/peer_bulletin.pdf). Therefore, the report had to be
`peer-reviewed in accordance with the requirements of both Sections II and III of OMB’s
`Bulletin.
`
`The peer-review process differed from the type used by journals. The effort by Messrs.
`Dalmotas, Jacobus and Lie was essentially consultation to identify shortcomings in the draft and
`help NHTSA strengthen the report. We in NHTSA specifically requested and arranged for these
`three reviewers. The review process is on record – their comments on the draft may be viewed
`in the NHTSA docket for this report. The publication of this report does not necessarily imply
`that they “endorsed” it or agreed with its findings. You may read their comments in the docket
`to see what they agreed or disagreed with in the draft. We have tried to address all of the
`comments in our revised report (but we did not send it back to them for a second round of
`review). The text and footnotes of the report single out some of the reviewers’ comments that
`instigated additions or revisions to the analyses.
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`viiiViii
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`EXECUTIVE SUMMARY
`
`
`
`Side air bags with head protection, such as torso bags with head curtains reduce fatality risk in
`side impacts by an estimated 24 percent for the nearside occupant, the person seated adjacent to
`the struck side of the vehicle. That benefit adds to the effect of improved side structures and
`padding built into passenger cars during the 1980s and 90s that had already reduced fatality risk
`for nearside occupants by 33 percent in 2-door cars and 17 percent in 4-door cars.
`
`In 2003, over 9,000 fatalities, approximately 29 percent of all occupant fatalities in cars and
`LTVs (light trucks and vans – i.e., pickup trucks, sport utility vehicles, minivans and full-size
`vans) began with a side impact. The side of a vehicle, especially the door area adjacent to the
`occupant is intrinsically a vulnerable spot: there is limited space and structure between the
`occupant and the outside. Side impacts can also be difficult to avoid. Even the most prudent
`driving on our part cannot eliminate the risk that another vehicle will fail to yield, run a red light
`or turn without warning across our path.
`
`Since the 1970’s, the National Highway Traffic Safety Administration (NHTSA), the
`manufacturers and others in the safety community have worked hard to reduce fatality risk in
`side impacts, especially for the most vulnerable occupant, the “nearside” occupant: the driver in
`a left-side impact and the right-front passenger in a right-side impact. The effort resulted in the
`four tangible improvements in side impact protection that are evaluated in this report:
`
`1. Upgrading the side structure of passenger cars to slow down and reduce the extent of
`door intrusion into the passenger compartment after a side impact. Improvements include
`redesigning or strengthening the beams that horizontally reinforce the doors; the pillars,
`sills, and roof rails that surround the doors; and the cross-members or seat structures that
`resist lateral crush.
`
`2. Installation of thick, energy absorbing padding within the door structure to reduce the
`probability of occupant injury after the door interior contacts the occupant.
`
`And two types of side air bags:
`
`3. Torso air bags that deploy from the seat or the door to provide an energy-absorbing
`cushion between the occupant’s torso and the vehicle’s side structure. Torso air bags
`cover a much larger impact area and absorb more energy than padding.
`
`4. Head-protection air bags that complement the torso bags by cushioning head impacts
`with the side structure and possibly barring occupant ejection through side windows.
`Head protection may consist of:
`
`a. “Torso/head combination bags” that deploy from the seat to protect the torso but
`also extend upward far enough to protect the head impact zones around the side
`window, or
`
`b. “Head curtains” or “inflatable tubular structures” that drop down from the roof
`rail into the side-window area, separately from the torso bags.
`
`
`
`ix
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`

`
`
`During the 1980’s, NHTSA and the safety community developed a procedure for assessing
`injury risk in side impacts, including:
`
`• A crash test configuration simulating a severe intersection collision in which a fast-
`moving vehicle strikes a slow-moving vehicle in the door, at a right angle.
`
`• A Moving Deformable Barrier (MDB) simulating a generic striking vehicle.
`
`• A Thoracic Trauma Index (TTI) that predicts the severity of thoracic injuries when
`occupants’ torsos contact the interior side surface of the struck vehicle.
`
`• A Side Impact Dummy (SID) on which TTI can be reliably measured in side impact tests.
`The injury score measured on the dummy is called TTI(d).
`
`In 1990 NHTSA amended Federal Motor Vehicle Safety Standard (FMVSS) 214, Side Impact
`Protection for passenger cars, adding a 33.5 mph impact by an MDB into the side of the car and
`limiting TTI(d) for a SID in the nearside position up to a maximum of 90 in 2-door cars and 85
`in 4-door cars. The requirement was phased-in to passenger cars during model years 1994 to
`1997 and subsequently extended to LTVs, effective in model year 1999, limiting TTI(d) to 85.
`
`The manufacturers redesigned structures and/or affixed padding to substantially reduce average
`TTI(d) during and, to some extent, even before the 1994-1997 phase-in of FMVSS 214. But
`their actions varied from model to model. Many 2-door cars, with their long, vulnerable door
`areas, received extensive structural reinforcement or other redesign, whereas some of the heavier
`4-door cars and most LTVs needed little or no change to meet FMVSS 214. In many cars,
`manufacturers improved TTI(d) well beyond the NHTSA requirements.
`
`Manufacturers have continued to improve side impact protection by installing side air bags
`and/or upgrading side structures as they redesigned their cars. Torso bags first appeared on
`production vehicles in 1996 and head-protection air bags in 1998. By model year 2003, nearly
`30 percent of new cars were equipped with torso bags and nearly 20 percent with head-protection
`air bags. NHTSA does not require side air bags, but encourages all improvements to side impact
`protection, including side air bags, by informing consumers about the performance of new
`vehicles. The agency’s New Car Assessment Program (NCAP) includes a rating system of one
`star (worst) to five stars (best) on a side impact test. Buying a Safer Car brochures specify what
`make-models are equipped with torso and/or head air bags. The information is available to
`consumers on the agency’s web site, www.safercar.gov.
`
`TTI(d) performance at the 33.5 mph test speed of FMVSS 214 demonstrates how much cars have
`improved over the years. In 2-door cars, TTI(d) for front-seat occupants has improved, on the
`average, from 114 in baseline 1981-1985 models to 44 in models equipped with side air bags and
`meeting FMVSS 214: amazing progress on a difficult safety problem.
`
`This report investigates if the improvements in side impact protection have saved lives in actual
`crashes, based on statistical analyses of crash data. The Government Performance and Results
`Act of 1993 and Executive Order 12866 require agencies to evaluate the benefits of their existing
`regulations. The statistical analyses use calendar year 1993-2005 crash data from the Fatality
`
`
`
`x
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`

`

`
`
`Analysis Reporting System (FARS) and the General Estimates System (GES) of the National
`Automotive Sampling System (NASS). The analyses are divided into two main sections:
`
`• Effect of TTI(d) improvements by structure and padding (without side air bags) on the
`fatality risk of front-seat occupants (drivers and right-front passengers) in passenger cars.
`Many of the improvements date to the mid-1990s. By now, the cars have been on the
`road for nearly a decade. While there is a fair amount of uncertainty, the results are
`essentially final in the sense that most of the eventual data are already in hand.
`o A parallel analysis for compact pickup trucks did not show a statistically
`significant effect.
`
`• Effect of side air bags – torso bags and/or head-protection air bags – for front-seat
`occupants of cars and LTVs. Side air bags, especially head air bags began to appear in
`large numbers only after 2000. Analyses already show statistically significant results, but
`more data are on the way. The findings of this report will be updated periodically during
`the next five years.
`o Side air bags are principally designed to protect nearside occupants but might
`conceivably also benefit farside occupants: the driver in a right-side impact and
`the right-front passenger in a left-side impact. Statistical analyses separately
`focus on nearside and farside occupants.
`
`The main findings of this report are that structural improvements and padding for cars, and side
`air bags for cars and LTVs have significantly reduced occupants’ fatality risk. The two types of
`side air bags – torso bags and head-protection air bags – make substantial and complementary
`contributions to fatality reduction for nearside occupants. Head curtains (or inflatable tubular
`structures) also appear to have a significant benefit for farside occupants of passenger cars. The
`public will obtain the most protection if they have all of these improvements: structures and
`padding that meet or exceed the requirements of FMVSS 214, torso bags and head curtains. The
`combined effects are impressive, amounting to a 42 percent cumulative fatality reduction in
`2-door cars, and a 30 percent reduction in 4-door cars.
`
`The findings and conclusions of the statistical analyses are the following:
`
`
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`
`
`SIDE IMPACT PERFORMANCE OVER THE YEARS
`
`The risk of chest injury in a side impact is measured on a specially designed side impact dummy
`during a crash test in the FMVSS 214 configuration, a 33.5 mph impact by a moving deformable
`barrier into the side of the test vehicle. Accelerations measured on the upper and lower ribs and
`lower spine are combined into a Thoracic Trauma Index for the dummy - TTI(d). TTI(d) gauges
`occupants’ injury risk in nearside impacts: the lower the TTI(d), the lower the risk of injury.
`Reductions in the average TTI(d) of the many vehicles NHTSA has tested over the years
`demonstrate improved safety in side impacts.
`
`• TTI(d) for front-seat occupants in the FMVSS 214 test configuration, by model year,
`averaged:
`
`
`
`
`
`FMVSS 214 requirement
`
`Actual performance:
`
`1981-1985 baseline TTI(d)
`
`1993-1996, but not yet 214 certified
`
`1994-2003, 214-certified – no side air bags
`
`1996-2003, 214-certified – with side air bags
`
`2-Door Cars
`
`4-Door Cars
`
`90
`
`114
`
`95
`
`69
`
`44
`
`85
`
`85
`
`71
`
`63
`
`48
`
`•
`
`•
`
`In 2-door cars, TTI(d) improved by 45 units since 1981-1985 without side air bags and an
`additional 25 units with side air bags, for a total of 70. Average performance was
`originally much worse than the FMVSS 214 requirement and is now much better.
`
`In 4-door cars, TTI(d) improved by 22 units since 1981-1985 without side air bags and an
`additional 15 units with side air bags, for a total of 37. Average performance was once
`about the same as the FMVSS 214 requirement and is now much better.
`
`• TTI(d) performance used to be much worse in 2-door cars than in 4-door cars; it is now
`nearly the same.
`
`
`
`xii
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`

`
`
`EFFECT OF TTI(d) IMPROVEMENT WITHOUT SIDE AIR BAGS IN PASSENGER CARS
`
`• During the model year 1994-1997 phase-in of FMVSS 214, approximately:
`o 56 percent of cars received substantial structural modifications, usually
`accompanied with padding.
`o 21 percent received padding with minor structural modifications.
`o
` 6 percent received padding only.
`o 17 percent remained essentially unchanged from previous model years.
`• This report identifies 15 make-models that substantially improved TTI(d), by a known
`amount, without side air bags: from an average of 85 to 62, a 23-unit improvement.
`Fatality risk of nearside front-seat occupants in multivehicle crashes decreased by a
`statistically significant 18 percent in these models (90 percent confidence bounds, 7 to 28
`percent).
`
`• For passenger cars with TTI(d) in the below-90 range, each unit improvement of TTI(d)
`without side air bags is associated with an estimated 0.863 percent fatality reduction for
`nearside occupants in multivehicle crashes (confidence bounds, 0.33 to 1.46 percent).
`o The fatality reductions for nearside occupants in single-vehicle crashes and for
`farside occupants were not statistically significant.
`
`• For pre-FMVSS 214, 2-door cars with TTI(d) in the 90+ range, each unit improvement of
`TTI(d) was associated with an estimated 0.927 percent fatality reduction for all occupants
`in side impacts (confidence bounds, 0.52 to 1.33 percent).
`
`•
`
`•
`
`In 2-door cars, the cumulative effect of reducing TTI(d) from 114 (1981-1985 baseline)
`to 69 (post-FMVSS 214 without side air bags) is a 33 percent fatality reduction for
`nearside occupants in multivehicle crashes (confidence bounds, 18 to 47 percent).
`
`In 4-door cars, the cumulative effect of reducing TTI(d) from 85 (1981-1985 baseline) to
`63 (post-FMVSS 214 without side air bags) is a 17 percent fatality reduction for nearside
`occupants in multivehicle crashes (confidence bounds, 7 to 27 percent).
`
`• TTI(d) improvement by structures and padding in passenger cars saved an estimated 803
`lives in calendar year 2003.
`
`•
`
`If every passenger car on the road in 2003 had been equipped with these improvements,
`they would have saved an estimated 1,143 lives.
`
`
`
`xiii
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`

`
`
`EFFECT OF SIDE AIR BAGS IN CARS AND LTVs
`
` Nearside occupants
`
`• Torso bags plus head protection in passenger cars reduces the fatality risk of nearside
`front-seat occupants in single- and multivehicle crashes by a statistically significant 24
`percent (90 percent confidence bounds, 4 to 42 percent).1
`o The data also show a statistically significant fatality reduction in LTVs and
`suggest that the effectiveness may be the same as in cars.
`o The available data do not show a difference in fatality reduction between the two
`types of head air bags: head curtains (or inflatable tubular structures) and
`torso/head combination bags.
`
`• Torso bags alone reduce the fatality risk of nearside occupants in passenger cars by an
`estimated 12 percent (confidence bounds, -3 to +23 percent).
`o Current data also suggest similar reductions for LTV occupants.
`• Through 2005, there were few vehicles equipped with head curtains only (no torso bags):
`not enough for a separate statistical analysis. However, the preceding results suggest that
`torso bags and head air bags are both effective in nearside impacts and make
`approximately equal contributions to fatality reduction.
`
` Farside occupants
`
`• Specific mechanisms whereby side air bags mitigate injuries in farside impacts have not
`yet been widely demonstrated or quantified by testing.
`
`• Nevertheless, statistical analyses of FARS and GES data show significant reductions of
`fatality risk for head curtains plus torso bags in farside impacts to passenger cars.
`
`• Furthermore, analyses of life-threatening injuries to farside occupants in passenger cars
`without side air bags suggest that head curtains or inflatable tubular structures could have
`benefited unrestrained occupants – or even belted drivers if no passenger had been sitting
`between them and the right side of the car – because:
`o Head curtains would have deployed and covered areas responsible for a large
`proportion of the life-threatening injuries, and
`
`
`1 A small portion of this effectiveness may actually be due to energy-absorbing materials (other than air bags)
`installed to meet the FMVSS 201 upgrade of head-impact protection. NHTSA will evaluate FMVSS 201 in the
`future; this report only addresses its interaction with side air bags. In many make-models, the introduction of head
`air bags coincided with FMVSS 201 certification; nevertheless, the energy-absorbing materials remained largely
`unchanged in the year that head air bags were introduced, and for that reason could not have accounted for a large
`portion of the fatality reduction for those make-models in that year.
`
`
`
`xiv
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`

`
`
`o In most of those impacts, the head curtains would still have been at least partially
`inflated at the time the farside occupant contacted them.
`
`• A 24 percent fatality reduction is estimated (same as for nearside occupants) for head
`curtains plus torso bags in farside impacts to passenger cars – for unrestrained occupants
`and for belted drivers riding alone in the front seat.
`
`• With the limited crash data available to date, no consistently significant fatality reduction
`was found and, for now, none is claimed in farside impacts for:
`o LTVs (with any type of side air bags),
`o Torso bags alone or torso/head combination bags in cars, or
`o Belted occupants, when somebody sits between them and the far side.
` Occupant ejection
`
`• Head curtains reduced the risk of fatal occupant ejection in side impacts by a statistically
`significant 30 percent.
`o Through model year 2003, head air bags in passenger cars were only designed to
`deploy in side impacts. Head curtains with rollover sensors began to appear in
`selected LTVs during mid-model year 2002. Crash data were not sufficient to
`evaluate to what extent this promising technology reduces ejections in rollover
`crashes.
`
` Overall
`
`• Side air bags could have saved an estimated 1,791 lives in calendar year 2003 if every
`passenger car and LTV on the road had been equipped with head curtains (or inflatable
`tubular structures) plus torso bags and if every LTV on the road had been equipped with
`torso bags plus head protection. However, the number of lives saved if all vehicles on the
`road were to have side air bags in a future year would be smaller than 1,791, since:
`o The long-term shift of the on-road fleet from cars to LTVs will reduce the number
`of potentially fatal side impacts because LTVs are less vulnerable, when struck in
`the side, than cars.
`o The increasing proportion of vehicles equipped with Electronic Stability Control
`will further reduce the number of potentially fatal side impact and rollover crashes
`by preventing these crashes altogether.
`
`The estimation of future lives saved is beyond the scope of this report, but will be
`addressed in NHTSA’s forthcoming Final Regulatory Impact Analysis to add a pole test
`to FMVSS 214.
`
`
`
`xv
`
`

`

`
`
`COMBINED EFFECT OF IMPROVED STRUCTURE, PADDING, AND SIDE AIR BAGS
`
`• Side impact protection could have saved an estimated 2,934 lives in calendar year 2003 if
`every car on the road had been equipped with head curtains, torso bags and FMVSS 214
`side structures/padding, and if every LTV on the road had been equipped with torso bags
`plus head protection.
`
`• Relative to 1981-1985 baseline cars, the combination of head curtains, torso bags and
`FMVSS 214 side structures/padding reduces fatality risk of drivers and right-front
`passengers in all side impacts by:
`o 42 percent in 2-door cars.
`o 30 percent in 4-door cars.
`In LTVs, torso bags plus head protection reduce fatality risk of drivers and right-front
`passengers in all side impacts by 15 percent.
`
`•
`
`
`
`
`
`xvi
`
`

`

`
`
`CHAPTER 1
`
`OCCUPANT PROTECTION IN SIDE IMPACTS
`
`
`
`Federal Motor Vehicle Safety Standard (FMVSS) 214, amended in 1990 to assure occupant
`protection in a dynamic test that simulates a side impact collision, is one of the most important
`safety regulations issued by NHTSA. The requirement was phased-in to passenger cars during
`model years 1994 to 1997. Crash data are now available to evaluate whether this regulation and
`the vehicle modifications that improve performance in the side impact test, including upgraded
`structure, padding and side air bags are effective in reducing fatality risk in actual side impact
`crashes of production passenger cars.
`
`1.1 The side impact problem in passenger cars
`Number of fatalities: Figure 1-1 shows that side impacts accounted for close to 9,000 occupant
`fatalities per year in passenger cars and LTVs (light trucks and vans, including pickup trucks,
`SUVs, minivans and full-size vans under 10,000 pounds GVWR), year after year, from 1975
`through 2004:2
`
`Figure 1-1: Car and LTV Occupant Fatalities in All Side Impacts, 1975-2004
`
`10000
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`9000
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`8000
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`7000
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`6000
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`5000
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`4000
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`3000
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`2000
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`1000
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`0
`1975
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`1976
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`1977
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`1978
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`1979
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`1980
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`1981
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`1982
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`1983
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`1984
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`1985
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`1986
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`1987
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`1988
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`1989
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`1990
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`1991
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`1992
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`1993
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`1994
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`1995
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`1996
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`1997
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`1998
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`1999
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`2000
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`2001
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`2002
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`2003
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`2004
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`LTVs
`Cars
`
`
`
`
`2 Dainius Dalmotas recommended trend analyses of side impact fatalities in his review of this report. Figures 1-1 –
`1-9 address issues he raised, but the data in these figures were generated, at NHTSA, especially for this report.
`
`
`
`1
`
`

`

`
`
`The number of fatalities stayed about the same while vehicle miles of travel (VMT) more than
`doubled. The proportion of these fatalities in LTVs increased in parallel with the increasing ratio
`of LTVs to cars in the on-