- Email: [email protected]
Rear-Seat Motor Vehicle Travel in the U.S.
Brief Reports
Rear-Seat Motor Vehicle Travel in the U.S. Using National Data to Define a Population at Risk Matthew J. Trowbridge, MD, MPH, Richard Kent, PhD Background: Recent studies suggest that the relative protection offered by rear seating in motor vehicle crashes has decreased, potentially reflecting disproportionate advancements in front-seat safety technology. Safe adaptation of advanced front-seat restraint systems for the rear-seat environment will require exposure data that are currently unavailable. Purpose:
This study uses national data to quantify rear-seat occupancy patterns, restraint use, and annual travel exposure in the U.S. in order to support the development of advanced crash protection systems for rear-seat motor vehicle occupants.
Methods:
Data from the 2000 –2006 National Automotive Sampling System Crashworthiness Data System and 2001 National Household Transportation Survey were analyzed in 2008 to quantify occupancy patterns (e.g., seat position, restraint use) and annual person-trips for rear-seat passengers in the U.S.
Results:
The overall proportion of person-trips by rear-seat occupants is relatively low (12.9%); however national at-risk exposure remains significant (approximately 39 billion annual person-trips). Annual rear-seat travel exposure is similar among children ⱕ12 years and adults (18.9 vs 19.1 billion person-trips) despite the fact that children are proportionally much more likely to ride in rear positions (79.3% vs 7.4%). Restraint use among adult rear-seat occupants was also much lower than among front-seat occupants (50.4% vs 82.2%).
Conclusions: While rear-seat occupancy is relatively low compared with front-seat occupancy at-risk rear-seat travel by both child and adult passengers in the U.S. remains significant. Restraint use by rear-seat occupants is much lower than that among front-seat passengers, particularly among adults and older children, substantially increasing injury risk. Development of future crash protection systems for rear-seat passengers must account for these exposure patterns to ensure safe and effective integration into production vehicles. (Am J Prev Med 2009;37(4):321–323) © 2009 American Journal of Preventive Medicine
Introduction
R
esearch continues to demonstrate a lower overall fatality risk for rear-seat passengers compared with matched front-seat passengers in motor vehicle crashes.1 However, the relative protection offered by rear-seat positions is decreasing, and among certain subpopulations, such as restrained occupants ⱖ50 years, has become negative.2,3 This trend likely reflects disproportionate advancements in frontseat crash protection compared with the rear seat.4,5 Preliminary assessments of front-seat technologies such as pre-tensioning and load-limiting seatbelts in the rear-seat environment indicate both feasibility and benefit,6 yet rear-seat exposure data necessary for safe integration into production vehicles are unavailable. From the Department of Emergency Medicine, University of Virginia Health School of Medicine and Center for Applied Biomechanics, University of Virginia School of Engineering, Charlottesville, Virginia Address correspondence and reprint requests to: Matthew Trowbridge, MD, MPH, Department of Emergency Medicine, University of Virginia Health System, P.O. Box 800699, Charlottesville VA 229080699. E-mail: [email protected].
Failure to sufficiently anticipate occupancy patterns prior to introducing new safety countermeasures in motor vehicles can be dangerous; a notable example is first-generation passenger airbags that proved potentially fatal to child passengers traveling in the front seat during low-speed crashes.7 The objective of this study was to quantify rear-seat occupancy patterns, restraint use, and annual travel exposure in the U.S. These data will help support the development of advanced crash protection systems for rear-seat motor vehicle occupants.
Methods In 2008, rear-seat motor vehicle travel exposure in the U.S. was investigated using two federal sources: the 2000 –2006 National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and the 2001 National Household Transportation Survey (NHTS). NASS-CDS provides nationally representative data regarding motor vehicle crashes based on a weighted annual sample of approximately 5000 police-reported collisions.8 NASS-CDS includes detailed information for each
Am J Prev Med 2009;37(4) © 2009 American Journal of Preventive Medicine • Published by Elsevier Inc.
0749-3797/09/$–see front matter doi:10.1016/j.amepre.2009.05.021
321
crash, including seat posiTable 1. Seat row and estimated annual person-trips for motor vehicle occupants in the U.S. tion and restraint status Seat row na Weighted % (95% CI) Annual person-tripsb SD of each involved vehicle occupant. Front 7524 5,198,921 87.1 (85.4, 88.9) 263,356,464,752 875,564,533 The NHTS is a periodic Rear 1287 768,492 12.9 (11.2, 14.6) 38,928,266,637 559,693,684 a nationally representative Unweighted cases in 2000 –2006 NASS-CDS b survey of travel behavior.9 Estimated annual person-trips in the U.S. by passengers in each seat row NASS-CDS, National Automotive Sampling System, Crashworthiness Data System The 2001 NHTS collected information from 66,000 U.S. households through national level, annual rear-seat travel exposure was simtelephone surveys and trip diaries used to document travel ilar for both age groups (18.9 vs 19.1 billion personduring an assigned travel day. Information such as mode of trips for children and adults, respectively). Older pastravel, purpose, and distance are recorded for each trip; sengers (aged ⬎65 years) were relatively infrequent however data such as seat position during vehicle trips or rear-seat occupants. Only 3.6% of older passengers seatbelt use are not. Weights are included in the data set to were rear seated, accounting for only 717 million adjust for sampling error and bias when calculating national annual U.S. person-trips. estimates.
Analysis Methodology Seating position and restraint use data from NASS-CDS were combined with trip information from NHTS to investigate rear-seating position, restraint use, and overall travel exposure at a national level. First, the estimated proportion (pˆ) of national in-transit motor vehicle occupants who were rear seated was calculated from NASS-CDS. Second, an estimate of annual person-trips (Xˆ) by rear-seat passengers was calculated by multiplying the estimated proportion of rear-seat occupants by a weighted national estimate of total annual persontrips (Nˆ) derived from NHTS data: ˆ X⫽ˆ N · ˆp .
(1)
By assuming that pˆ and Nˆ are independent, the estimated variance for each rear-seat person-trip estimate, vˆ(Xˆ), was then calculated as ˆ)⫽ˆ ˆ ) ⫹ (N ˆ ) · (pˆ ). ˆ(X N · (pˆ ) ⫹ ˆp · (N
(2)
Analysis of NASS-CDS data was limited to “not at fault” vehicles (i.e., not responsible for the crash occurring) as a proxy for general in-transit vehicles because the demographics and occupancy patterns of at-fault drivers and passengers may not be generally representative.
Most rear-seat occupants were seated in an outboard position (83.2%; 95% CI⫽79.9%, 86.5%), including 80.5% (95% CI⫽63.2%, 97.9%) of children aged ⱖ2 years. In contrast, 63.1% (95% CI⫽40.9%, 85.3%) of rear-seated infants (aged ⬍2 years) were seated in the center position.
Rear-Seat Restraint Use Restraint use by rear-seat passengers was much lower than it was among front-seat occupants (50.4% vs 82.2%, Table 2) and varied by age. For example, the proportion of belted older rear-seat passengers (aged ⬎65 years) was approximately 10% higher than that of passengers aged 13– 65 years (91.0% vs 80.1%, respectively). Similarly, while the large majority of children aged ⱕ12 years in rear seats were using some form of restraint (88.7%; 95% CI⫽80.0%, 97.5%), older children (aged 8 –12 years) were much more likely to be unrestrained (20.7%; 95% CI⫽5.4%, 36.0%) than children in younger age groups.
Discussion Results Seating Position and Annual Travel Exposure
This study provides national estimates of rear-seat occupancy and travel exposure in the U.S. The results demonstrate that while that the overall proportion of person-trips taken as a rear-seat occupant in the U.S. is relatively low (12.9%), at-risk travel exposure by rearseat passengers at a national level is substantial (approx-
Overall, 12.9% of in-transit U.S. motor vehicle occupants from 2000 to 2006 traveled in the rear seat (95% CI⫽11.2%, 14.6%). Total annual travel exposure for rear-seat passengers was Table 2. Restraint status by seat row for motor vehicle occupants in the U.S. approximately 39 bilSeatbelt use na Weighted lion person-trips (Ta- Seat row No 1722 884,963 ble 1). Children aged Front Yes 5510 4,074,433 ⬍12 years were proporNo 695 381,580 tionally much more Rear Yes 592 386,913 likely to be rear-seat All rows No 2417 1,266,542 passengers than adults Yes 6102 4,461,346 13–64 years (79.3% vs aUnweighted cases in 2000 –2006 7.4%). However, at a NASS-CDS, National Automotive Sampling System, Crashworthiness Data System 322
American Journal of Preventive Medicine, Volume 37, Number 4
% (95% CI) 17.9 (14.9, 20.8) 82.2 (79.2, 85.1) 49.7 (37.6, 61.7) 50.4 (38.3, 62.4) 22.1 (19.4, 24.9) 77.9 (75.1, 80.7)
www.ajpm-online.net
imately 39 billion annual person-trips). In addition, despite the fact that children aged ⬍12 years are more likely to travel in the rear seat than adults, overall rear-seat travel exposure at a national level for the two groups is similar (18.9 vs 19.1 billion annual persontrips). This demonstrates that improving crash protection for adult rear-seat passengers must continue to be a priority in the midst of efforts to develop and regulate advanced crash injury countermeasures for children in the rear-seat environment. This analysis also demonstrates much lower seatbelt use in the rear seat (50%) compared with the front seat (82%). This finding is consistent with previous observational studies in the U.S.10 as well as recent Japanese studies,11 which show an even greater disparity (92.4% front vs 8.1% rear). Confirmation of low rear-seat restraint use has significant implications for injury prevention because many advanced safety technologies (e.g., force-limiting seatbelts) require elective restraint use in order to be effective. Unrestrained rear passengers also increase the risk of severe injury to front-seat occupants by a factor of approximately two.12–14 Finally, the finding that nearly 37% of rear-seated children aged ⬍2 years ride in an outboard position reveals an untapped opportunity for safety benefit. Recent research suggests that the rear center seating position confers a 43% reduction in significant injury risk for children aged 0 –3 years compared with outboard positions.15 The primary strengths of this study are its use of nationally representative data and the calculations of annual travel-exposure estimates, specifically for rearseat passengers. A key limitation is the reliance on crash data to estimate in-transit rear-seat occupancy and restraint use. Crash-involved occupants may not be fully representative of the general in-transit population in terms of seating position or other travel behaviors. For example, seatbelt usage is generally over-reported in crash-based data sets.16 It is therefore possible that the estimates of rear-seat restraint use reported here overestimate actual use. However, comparison with previous studies17 suggests that potential over-reporting is relatively small.
Conclusion While rear-seat occupancy is relatively low compared with front-seat occupancy, at-risk rear-seat travel by both child and adult passengers in the U.S. remains
October 2009
significant. Restraint use by rear-seat occupants is much lower than it is among front seat passengers, particularly among adults and older children, substantially increasing injury risk. Development of future crash protection systems for rear-seat passengers must account for these exposure patterns to ensure safe and effective integration into production vehicles. No financial disclosures were reported by the authors of this paper.
References 1. Smith KM, Cummings P. Passenger seating position and the risk of passenger death in traffic crashes: a matched cohort study. Inj Prev 2006;12(2):83– 6. 2. Kent R, Forman J, Parent D, Kuppa S. The feasibility and effectiveness of belt pretensioning and load limiting for adults in the rear seat. Int J Vehicle Saf 2007;2(4):378 – 403. 3. Kuppa S, Saunders J, Fessahaie O. Rear seat occupant protection in frontal crashes. In: Proceedings of the 19th International Technical Conference on the Enhanced Safety of Vehicles, 2005; Washington DC, 2005. 4. Foret-Bruno J, Trosseille X, Le Coz J-Y, et al. Thoracic injury risk in frontal car crashes with occupant re-strained with belt load limiter. SAE Technical Paper Series 983166. In: SAE. Warrendale PA: Society of Automotive Engineers, 1998. 5. Walz M. NCAP test improvements with pretensioners and load limiters. Traffic Inj Prev 2004;5(1):18 –25. 6. Kent R, Forman J, Parent D, Kuppa S. Rear seat occupant protection in frontal crashes and its feasibility. In: 21st International Technical Conference on the Enhanced Safety of Vehicles, 2007. 7. Huff GF, Bagwell SP, Bachman D. Airbag injuries in infants and children: a case report and review of the literature. Pediatrics 1998;102(1):e2. 8. National Highway Traffic Safety Administration. Crashworthiness Data System (CDS)-analytical user manual, 2007 file. Washington DC: United States Department of Transportation, 2007. 9. Federal Highway Administration. 2001 National Household Travel Survey. Washington DC: U.S. Department of Transportation, 2001. 10. Ye T, Pickrell T. Seat belt use in rear seats in 2007. Washington DC: U.S. Department of Transportation, 2008. 11. Mizuno K, Ikari T, Tomita K, Matsui Y. Effectiveness of seatbelt for rear seat occupants in frontal crashes. In: 20th International Technical Conference on the Enhanced Safety of Vehicles, 2007; Washington DC: U.S. Department of Transportation, 2007. 12. Broughton J. The actual threat posed by unrestrained rear seat car passengers. Accid Anal Prev 2004;36(4):627–9. 13. Ichikawa M, Nakahara S, Wakai S. Mortality of front-seat occupants attributable to unbelted rear-seat passengers in car crashes. Lancet 2002; 359(9300):43– 4. 14. Mayrose J, Jehle D, Hayes M, Tinnesz D, Piazza G, Wilding GE. Influence of the unbelted rear-seat passenger on driver mortality: “the backseat bullet.” Acad Emerg Med 2005;12(2):130 – 4. 15. Kallan MJ, Durbin DR, Arbogast KB. Seating patterns and corresponding risk of injury among 0- to 3-year-old children in child safety seats. Pediatrics 2008;121(5):e1342–7. 16. Malliaris A, DeBlois J. Overstated safety belt use rates— evidence, consequences, and remedies. Paper 980351. In: SAE: Society of Automotive Engineers, 1998. 17. Glassbrenner D, Ye T. Child restraint use in 2007— use of correct restraint types. Washington DC: National Highway Traffic Safety Administration, 2008.
Am J Prev Med 2009;37(4)
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Rear-Seat Motor Vehicle Travel in the U.S. Using National Data to Define a Population at Risk Matthew J. Trowbridge, MD, MPH, Richard Kent, PhD Background: Recent studies suggest that the relative protection offered by rear seating in motor vehicle crashes has decreased, potentially reflecting disproportionate advancements in front-seat safety technology. Safe adaptation of advanced front-seat restraint systems for the rear-seat environment will require exposure data that are currently unavailable. Purpose:
This study uses national data to quantify rear-seat occupancy patterns, restraint use, and annual travel exposure in the U.S. in order to support the development of advanced crash protection systems for rear-seat motor vehicle occupants.
Methods:
Data from the 2000 –2006 National Automotive Sampling System Crashworthiness Data System and 2001 National Household Transportation Survey were analyzed in 2008 to quantify occupancy patterns (e.g., seat position, restraint use) and annual person-trips for rear-seat passengers in the U.S.
Results:
The overall proportion of person-trips by rear-seat occupants is relatively low (12.9%); however national at-risk exposure remains significant (approximately 39 billion annual person-trips). Annual rear-seat travel exposure is similar among children ⱕ12 years and adults (18.9 vs 19.1 billion person-trips) despite the fact that children are proportionally much more likely to ride in rear positions (79.3% vs 7.4%). Restraint use among adult rear-seat occupants was also much lower than among front-seat occupants (50.4% vs 82.2%).
Conclusions: While rear-seat occupancy is relatively low compared with front-seat occupancy at-risk rear-seat travel by both child and adult passengers in the U.S. remains significant. Restraint use by rear-seat occupants is much lower than that among front-seat passengers, particularly among adults and older children, substantially increasing injury risk. Development of future crash protection systems for rear-seat passengers must account for these exposure patterns to ensure safe and effective integration into production vehicles. (Am J Prev Med 2009;37(4):321–323) © 2009 American Journal of Preventive Medicine
Introduction
R
esearch continues to demonstrate a lower overall fatality risk for rear-seat passengers compared with matched front-seat passengers in motor vehicle crashes.1 However, the relative protection offered by rear-seat positions is decreasing, and among certain subpopulations, such as restrained occupants ⱖ50 years, has become negative.2,3 This trend likely reflects disproportionate advancements in frontseat crash protection compared with the rear seat.4,5 Preliminary assessments of front-seat technologies such as pre-tensioning and load-limiting seatbelts in the rear-seat environment indicate both feasibility and benefit,6 yet rear-seat exposure data necessary for safe integration into production vehicles are unavailable. From the Department of Emergency Medicine, University of Virginia Health School of Medicine and Center for Applied Biomechanics, University of Virginia School of Engineering, Charlottesville, Virginia Address correspondence and reprint requests to: Matthew Trowbridge, MD, MPH, Department of Emergency Medicine, University of Virginia Health System, P.O. Box 800699, Charlottesville VA 229080699. E-mail: [email protected].
Failure to sufficiently anticipate occupancy patterns prior to introducing new safety countermeasures in motor vehicles can be dangerous; a notable example is first-generation passenger airbags that proved potentially fatal to child passengers traveling in the front seat during low-speed crashes.7 The objective of this study was to quantify rear-seat occupancy patterns, restraint use, and annual travel exposure in the U.S. These data will help support the development of advanced crash protection systems for rear-seat motor vehicle occupants.
Methods In 2008, rear-seat motor vehicle travel exposure in the U.S. was investigated using two federal sources: the 2000 –2006 National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and the 2001 National Household Transportation Survey (NHTS). NASS-CDS provides nationally representative data regarding motor vehicle crashes based on a weighted annual sample of approximately 5000 police-reported collisions.8 NASS-CDS includes detailed information for each
Am J Prev Med 2009;37(4) © 2009 American Journal of Preventive Medicine • Published by Elsevier Inc.
0749-3797/09/$–see front matter doi:10.1016/j.amepre.2009.05.021
321
crash, including seat posiTable 1. Seat row and estimated annual person-trips for motor vehicle occupants in the U.S. tion and restraint status Seat row na Weighted % (95% CI) Annual person-tripsb SD of each involved vehicle occupant. Front 7524 5,198,921 87.1 (85.4, 88.9) 263,356,464,752 875,564,533 The NHTS is a periodic Rear 1287 768,492 12.9 (11.2, 14.6) 38,928,266,637 559,693,684 a nationally representative Unweighted cases in 2000 –2006 NASS-CDS b survey of travel behavior.9 Estimated annual person-trips in the U.S. by passengers in each seat row NASS-CDS, National Automotive Sampling System, Crashworthiness Data System The 2001 NHTS collected information from 66,000 U.S. households through national level, annual rear-seat travel exposure was simtelephone surveys and trip diaries used to document travel ilar for both age groups (18.9 vs 19.1 billion personduring an assigned travel day. Information such as mode of trips for children and adults, respectively). Older pastravel, purpose, and distance are recorded for each trip; sengers (aged ⬎65 years) were relatively infrequent however data such as seat position during vehicle trips or rear-seat occupants. Only 3.6% of older passengers seatbelt use are not. Weights are included in the data set to were rear seated, accounting for only 717 million adjust for sampling error and bias when calculating national annual U.S. person-trips. estimates.
Analysis Methodology Seating position and restraint use data from NASS-CDS were combined with trip information from NHTS to investigate rear-seating position, restraint use, and overall travel exposure at a national level. First, the estimated proportion (pˆ) of national in-transit motor vehicle occupants who were rear seated was calculated from NASS-CDS. Second, an estimate of annual person-trips (Xˆ) by rear-seat passengers was calculated by multiplying the estimated proportion of rear-seat occupants by a weighted national estimate of total annual persontrips (Nˆ) derived from NHTS data: ˆ X⫽ˆ N · ˆp .
(1)
By assuming that pˆ and Nˆ are independent, the estimated variance for each rear-seat person-trip estimate, vˆ(Xˆ), was then calculated as ˆ)⫽ˆ ˆ ) ⫹ (N ˆ ) · (pˆ ). ˆ(X N · (pˆ ) ⫹ ˆp · (N
(2)
Analysis of NASS-CDS data was limited to “not at fault” vehicles (i.e., not responsible for the crash occurring) as a proxy for general in-transit vehicles because the demographics and occupancy patterns of at-fault drivers and passengers may not be generally representative.
Most rear-seat occupants were seated in an outboard position (83.2%; 95% CI⫽79.9%, 86.5%), including 80.5% (95% CI⫽63.2%, 97.9%) of children aged ⱖ2 years. In contrast, 63.1% (95% CI⫽40.9%, 85.3%) of rear-seated infants (aged ⬍2 years) were seated in the center position.
Rear-Seat Restraint Use Restraint use by rear-seat passengers was much lower than it was among front-seat occupants (50.4% vs 82.2%, Table 2) and varied by age. For example, the proportion of belted older rear-seat passengers (aged ⬎65 years) was approximately 10% higher than that of passengers aged 13– 65 years (91.0% vs 80.1%, respectively). Similarly, while the large majority of children aged ⱕ12 years in rear seats were using some form of restraint (88.7%; 95% CI⫽80.0%, 97.5%), older children (aged 8 –12 years) were much more likely to be unrestrained (20.7%; 95% CI⫽5.4%, 36.0%) than children in younger age groups.
Discussion Results Seating Position and Annual Travel Exposure
This study provides national estimates of rear-seat occupancy and travel exposure in the U.S. The results demonstrate that while that the overall proportion of person-trips taken as a rear-seat occupant in the U.S. is relatively low (12.9%), at-risk travel exposure by rearseat passengers at a national level is substantial (approx-
Overall, 12.9% of in-transit U.S. motor vehicle occupants from 2000 to 2006 traveled in the rear seat (95% CI⫽11.2%, 14.6%). Total annual travel exposure for rear-seat passengers was Table 2. Restraint status by seat row for motor vehicle occupants in the U.S. approximately 39 bilSeatbelt use na Weighted lion person-trips (Ta- Seat row No 1722 884,963 ble 1). Children aged Front Yes 5510 4,074,433 ⬍12 years were proporNo 695 381,580 tionally much more Rear Yes 592 386,913 likely to be rear-seat All rows No 2417 1,266,542 passengers than adults Yes 6102 4,461,346 13–64 years (79.3% vs aUnweighted cases in 2000 –2006 7.4%). However, at a NASS-CDS, National Automotive Sampling System, Crashworthiness Data System 322
American Journal of Preventive Medicine, Volume 37, Number 4
% (95% CI) 17.9 (14.9, 20.8) 82.2 (79.2, 85.1) 49.7 (37.6, 61.7) 50.4 (38.3, 62.4) 22.1 (19.4, 24.9) 77.9 (75.1, 80.7)
www.ajpm-online.net
imately 39 billion annual person-trips). In addition, despite the fact that children aged ⬍12 years are more likely to travel in the rear seat than adults, overall rear-seat travel exposure at a national level for the two groups is similar (18.9 vs 19.1 billion annual persontrips). This demonstrates that improving crash protection for adult rear-seat passengers must continue to be a priority in the midst of efforts to develop and regulate advanced crash injury countermeasures for children in the rear-seat environment. This analysis also demonstrates much lower seatbelt use in the rear seat (50%) compared with the front seat (82%). This finding is consistent with previous observational studies in the U.S.10 as well as recent Japanese studies,11 which show an even greater disparity (92.4% front vs 8.1% rear). Confirmation of low rear-seat restraint use has significant implications for injury prevention because many advanced safety technologies (e.g., force-limiting seatbelts) require elective restraint use in order to be effective. Unrestrained rear passengers also increase the risk of severe injury to front-seat occupants by a factor of approximately two.12–14 Finally, the finding that nearly 37% of rear-seated children aged ⬍2 years ride in an outboard position reveals an untapped opportunity for safety benefit. Recent research suggests that the rear center seating position confers a 43% reduction in significant injury risk for children aged 0 –3 years compared with outboard positions.15 The primary strengths of this study are its use of nationally representative data and the calculations of annual travel-exposure estimates, specifically for rearseat passengers. A key limitation is the reliance on crash data to estimate in-transit rear-seat occupancy and restraint use. Crash-involved occupants may not be fully representative of the general in-transit population in terms of seating position or other travel behaviors. For example, seatbelt usage is generally over-reported in crash-based data sets.16 It is therefore possible that the estimates of rear-seat restraint use reported here overestimate actual use. However, comparison with previous studies17 suggests that potential over-reporting is relatively small.
Conclusion While rear-seat occupancy is relatively low compared with front-seat occupancy, at-risk rear-seat travel by both child and adult passengers in the U.S. remains
October 2009
significant. Restraint use by rear-seat occupants is much lower than it is among front seat passengers, particularly among adults and older children, substantially increasing injury risk. Development of future crash protection systems for rear-seat passengers must account for these exposure patterns to ensure safe and effective integration into production vehicles. No financial disclosures were reported by the authors of this paper.
References 1. Smith KM, Cummings P. Passenger seating position and the risk of passenger death in traffic crashes: a matched cohort study. Inj Prev 2006;12(2):83– 6. 2. Kent R, Forman J, Parent D, Kuppa S. The feasibility and effectiveness of belt pretensioning and load limiting for adults in the rear seat. Int J Vehicle Saf 2007;2(4):378 – 403. 3. Kuppa S, Saunders J, Fessahaie O. Rear seat occupant protection in frontal crashes. In: Proceedings of the 19th International Technical Conference on the Enhanced Safety of Vehicles, 2005; Washington DC, 2005. 4. Foret-Bruno J, Trosseille X, Le Coz J-Y, et al. Thoracic injury risk in frontal car crashes with occupant re-strained with belt load limiter. SAE Technical Paper Series 983166. In: SAE. Warrendale PA: Society of Automotive Engineers, 1998. 5. Walz M. NCAP test improvements with pretensioners and load limiters. Traffic Inj Prev 2004;5(1):18 –25. 6. Kent R, Forman J, Parent D, Kuppa S. Rear seat occupant protection in frontal crashes and its feasibility. In: 21st International Technical Conference on the Enhanced Safety of Vehicles, 2007. 7. Huff GF, Bagwell SP, Bachman D. Airbag injuries in infants and children: a case report and review of the literature. Pediatrics 1998;102(1):e2. 8. National Highway Traffic Safety Administration. Crashworthiness Data System (CDS)-analytical user manual, 2007 file. Washington DC: United States Department of Transportation, 2007. 9. Federal Highway Administration. 2001 National Household Travel Survey. Washington DC: U.S. Department of Transportation, 2001. 10. Ye T, Pickrell T. Seat belt use in rear seats in 2007. Washington DC: U.S. Department of Transportation, 2008. 11. Mizuno K, Ikari T, Tomita K, Matsui Y. Effectiveness of seatbelt for rear seat occupants in frontal crashes. In: 20th International Technical Conference on the Enhanced Safety of Vehicles, 2007; Washington DC: U.S. Department of Transportation, 2007. 12. Broughton J. The actual threat posed by unrestrained rear seat car passengers. Accid Anal Prev 2004;36(4):627–9. 13. Ichikawa M, Nakahara S, Wakai S. Mortality of front-seat occupants attributable to unbelted rear-seat passengers in car crashes. Lancet 2002; 359(9300):43– 4. 14. Mayrose J, Jehle D, Hayes M, Tinnesz D, Piazza G, Wilding GE. Influence of the unbelted rear-seat passenger on driver mortality: “the backseat bullet.” Acad Emerg Med 2005;12(2):130 – 4. 15. Kallan MJ, Durbin DR, Arbogast KB. Seating patterns and corresponding risk of injury among 0- to 3-year-old children in child safety seats. Pediatrics 2008;121(5):e1342–7. 16. Malliaris A, DeBlois J. Overstated safety belt use rates— evidence, consequences, and remedies. Paper 980351. In: SAE: Society of Automotive Engineers, 1998. 17. Glassbrenner D, Ye T. Child restraint use in 2007— use of correct restraint types. Washington DC: National Highway Traffic Safety Administration, 2008.
Am J Prev Med 2009;37(4)
323