Contents
List of Abbreviations 6
Definitions of Terms 7
Executive Summary 9
1. Introduction 10
2. Sampling and Data Collection Methodology 10
3. The NCRUSS Data 11
3a. Overall Survey Sample 11
3b. Car Seat and Booster Seat Hardware 13
3c. Car Seat to Vehicle Installation 13
3d. Installation Methods of Car Seat to Vehicle 14
3e. Restraining of a Child in a Vehicle 15
3f. Interviewed Drivers' Response 18
4. Car Seat and Booster Seat Misuse 20
4a. Misuse by Installation Method 23
4b. Overall Misuse 25
5. Manufacturer Weight and Height Recommendations 27
6. Child Restraint Anchorage System (LATCH) Use 29
6a. LATCH Use in the NCRUSS 29
6b. Nonuse of Lower Anchors or Tethers 32
7. Summary 34
Appendix A. Sampling Methodology 35
A1. Sample Size 35
A2. Sampling 36
A3. Site Sampling 36
A4. Vehicle Sampling 38
A5. Person-Level Sampling 38
A6. Adjustments 39
Appendix B: Data Collection Methodology 40
B1. Data Collection Teams 40
B2. Data Collection Schedule 40
B3. Survey Forms and Variables 41
B4. Observational Data 41
B5. Inspection Data 41
B6. Interview Data 42
B7. Data Entry 42
B8. Quality Control 42
Appendix C: The NCRUSS Data 44
C1. Overall Survey Sample 44
C2. Car Seat to Vehicle Installation 49
C3. Installation Methods of Car Seat to Vehicle 51
C4. Installation by Lower Anchor Connectors-Only or Seat Belt-Only 53
C5. Installation by Lower Anchor Connectors and Tether Strap or Seat Belt and Tether 56
C6. Restraining of Child in Vehicle 59
Appendix D. List of Defined Misuses 62
Appendix E. Observed Misuse 63
Appendix F. Multiple Imputations 64
Table 1. Overall Survey Sample Characteristics 12
Table 2. Car Seat to Vehicle Installation by Seat Type 14
Table 3. Installation Method of Car Seat to Vehicle by Seat Type 15
Table 4. Restraining of Child in Booster or Vehicle Seat by Seat Type 16
Table 5. Restraining of Child in Car Seat by Seat Type 17
Table 6. Drivers' Confidence on Correct Type of Car Seat/Booster Seat Used 18
Table 7. Drivers' Confidence on Correct Installation of Car Seat/Booster 18
Table 8. Drivers' Knowledge 19
Table 9. Car Seat/Booster Seat Been Inspected 19
Table 10. Booster Seats Misuse by Seat Type 21
Table 11. Car Seats Misuse by Seat Type 22
Table 12. Misuse of Car Seats Installed to Lower Anchors by Seat Type 23
Table 13. Misuse of Car Seats Installed with Seat Belt by Seat Type 23
Table 14. Installation Misuse of Forward-Facing Car Seat by Installation Method 24
Table 15. Installation Misuse of Rear-Facing Car Seat by Installation Method 24
Table 16. Installation Misuse of Forward-Facing Car Seat by Installation Method 24
Table 17. Overall Misuse Percentages of Car Seats and Booster Seats Including Unknowns 25
Table 18. Imputed Overall Misuse Percentages of Car Seats and Booster Seats 26
Table 19. Child's Weight Relation to Manufacturer Limit by Car Seat/Booster Seat Type 27
Table 20. Child's Height Relation to Manufacturer Limit by Car Seat/Booster Seat Type 28
Table 21. Car Seat With Available Lower Anchor Connectors and Tether Strap or Only Lower Anchor Connectors by Seat Type 30
Table 22. Observed Car Seat Attachment to the Vehicle for Qualified Car Seats With Lower Anchors and Tether Anchor Available at the Car Seat's Particular Seating Position 30
Table 23. Misuse of Qualified Car Seats With Lower Anchors and Tether Anchor Available at the Car Seat's Particular Seating Position by Installation Method 31
Table 24. Observed Car Seat Attachment to the Vehicle for Qualified Car Seats as a Function of Lower Anchors and Tether Anchor Availability in the Vehicle but Not at Car Seat's Seating Position 32
Table 25. Seating Positions of Vehicles With Lower Anchors in the Seating Position, for Lower-Anchor-Connectors-Equipped Car Seats Where the Lower Anchors Connectors Were Not in Use 33
Table 26. Seating Positions of Vehicles With a Tether Anchor in the Seating Position, for Tether-Equipped Forward-Facing Car Seats Where the Tether Was Not in Use 33
Table A-1. Site Level Response Rates for the NCRUSS 37
Table C-1. Restraint Type by Age in Years 44
Table C-2. Restraint Type by Age Range 44
Table C-3. Restraint Type by Weight Category 45
Table C-4. Restraint Type by Height Category 45
Table C-5. Age in Years by Restraint Type 46
Table C-6. Age Range by Restraint Type 47
Table C-7. Weight Category by Restraint Type 47
Table C-8. Height Category by Restraint Type 48
Table C-9. Car Seat to Vehicle Installation by Seat Type 49
Table C-10. Lower Anchor Connectors Installations by Seat Type 51
Table C-11. Seat Belt Installations by Seat Type 52
Table C-12. Forward-Facing Car Seat to Vehicle Installation Methods 53
Table C-13. Seat Belt Installations of Forward-Facing Car Seat to Vehicle With Locked and Unlocked Retractors 54
Table C-14. Rear-Facing Car Seat to Vehicle Installation Methods With Locked and Unlocked Retractors 55
Table C-15. Seat Belt Installations of Rear-Facing Car Seat to Vehicle With Locked and Unlocked Retractors 55
Table C-16. Seat Belt Installations of Rear-Facing Infant Car Seat to Vehicle With Locked and Unlocked Retractors 56
Table C-17. Seat Belt Installations of Rear-Facing Convertible to Vehicle With Locked and Unlocked Retractors 56
Table C-18. Forward-Facing Car Seat to Vehicle Installation Methods Using Tether Strap 57
Table C-19. Forward-facing Car Seat to Vehicle With Locked and Unlocked Retractors 58
Table C-20. Shoulder Belt Position of Restrained Child in Booster Seat 59
Table C-21. Restraining of Child in Booster or Vehicle Seat 59
Table C-22. Restraining of Child in Car Seat 60
Table D-1. List of Defined Misuses 62
Table E-1. Number of Misuses per Identified Cases With Observed Misuse 63
Table E-2. Observed Misuse by Drivers' Confidence on Correct Installation of Car Seat/Booster 63
Table F-1. Overall Misuse Percentages of Car Seats and Booster Seats by Imputation Trials 64
Table F-2. Point and Variance Estimates of Overall Misuse by Imputation Trials 64