Effects of Recent Vehicle Design Changes on Safety Performance," Progress Reports for October 1977 Through 1979, Contract DOT-HS-7-Q1759
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TL DOT HS- 885-378 242 . R23 TOTS OF RECENT VEHICLE DESIGN CHANGES ON SAFETY PERFORMANCE Volume I D. iedmoocS B. Schmitz K. Friedman KINETIC RESEARCH department of TRANSPORTATION ( A Division of Minicars, Inc. ) 55 Depost Road GoSeta, California 93017 AUG 1 2 1980 " LIBRARY Contract No. DOT-HS- 7-01759 Contract Amount: $134,000 March 1879 FINAL REPORT This document is available to the U.S. public through the National Technical Information Service, Springfield, Virginia 22161 Prepared For U.S. DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration Washington, D.C. 20580 NOTICE This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for the contents or use thereof. 7^ X<f* , ^23 Technical Report Documentation Page /.]_ 1. Report No. 2. Government AccMtien No. 3. R.opi.nt » Catalog No. DOT rHS -80 5 -3 7 8 4. Till* and iubtifl# 5. R «porr Oo*b March 1979 Effects of Recent Vehicle Design Changes 6. R *t forming Orgam zanon Coo* On Safety Performance Volume I 8. Performing Orgam senen Report No. 7. Author' l) DEPARTMENT OF D. Redmond, B. Schmitz, K. Friedman j KR-TR-032 ' TRAN.^PnnThrr/^KT 9. R*rformi ng Organization Noma and Aodf.»s 10. Wqrfa Unit No. (TRAI5) Kinetic Research AUG 1 2 1980 (A Division of Minicars, Inc.) 11. Contract or Grartf No. 55 Depot Road DOT -HS-7-01 759 j •• library 13- Report and Period Co*or®d Gnlota r a Q3ni7 .. i Interim Report U. S. Department of Transportation October 1977-March 1979 National Highway Traffic Safety Administration 14. Sponsoring Ag.ney Coo. 400 Seventh St., S.W., Washington, DC 20590 1-5. Suppi ementary Notes 1 6. Abstract Design changes in 1974-1977 model year passenger cars have been identified and a preliminary evaluation has been made of the safety effects of design changes inspired by fuel economy requirements . The 1977 General Motors full-size cars and the Volkswagen Rabbit were found to be the only significant design change vehicles. These vehicles do not demonstrate significantly higher risks of fatality in acci- dents than do other vehicles of similar weight or roominess. Little change is observed in the aggregate characteristics of the 1974-1977 vehicle fleets, although the effects of the 1977 General Motors downsizing are observable. Methodologies have been implemented for the identification of vehicle design changes, for the calculation of observed fatality rates by make and model, and for the projection of future fatality and injury experience based on perceived trends in vehicle design and sales. There are a number of recommendations for further investigation of the effects of vehicle design on safety and for extension of the work to include 1978 and 1979 Model Year cars, Light Trucks and Vans. Volume I contains the text. Volume II contains the appendices. 17. K.y Word* 13. Distribution Sratomunt Automotive Design, Accident Analysis, Document is available to the U. S. Fatality Rate, Accident Environment public through the National Technical Projections, FARS, Vehicle Downsizing, Information Service, Springfield, Simulations Virginia 22161. 19. Socunry Classif. (of 'hi* r.oortl 20. S.cunty Cloasif. (of this pag.i 21. No. a t Rag.* 22. Rrie. Ill Unclassified Unclassified Form DOT F 1700.7 (3-72) Reproduction of completed page authorized i (FACTORS CONVERSION METRIC '86. Pnbt. M»sc. NBS see tables, 10:286. (tetailnd 3. Cl more No. and Catalog conversions SO S2.25. exact Price other Tor Measures, arxl tenacity}. Weiyhts 2.f>4 - ot ,o i Units • i i TABLE OF CONTENTS SECTION TITLE PAGE 1 INTRODUCTION........ 1 2 IDENTIFICATION OF AUTOMOBILE DESIGN CHANGE: 1974- 1977 3 2 . 1 Approach 3 2.2 Automotive Design Data Sets 4 2.3 Analysis of the Data. 9 3 ANALYSIS OF OBSERVED FATALITY RATES BY MODEL YEAR AND BY MAKE AND MODEL. 53 3.1 Preparation of FARS Data 54 3.2 Make and Model Identification in the FARS File 57 3.3 Annual Vehicle Mileages by Age of Vehicle.... 60 3.4 Observed Fatality Rates for All Vehicles by Model Year 69 3.5 Observed Fatality Rates by Make and Model for 1974-1977 Model Year Passenger Cars 101 4 RELATIONSHIP OF OBSERVED FATALITY RATE TO DESIGN PARAMETERS 125 4.1 General Considerations 125 4.2 Results of Stepwise Linear Regression Analysis 126 4.3 Conclusions 129 5 ASSESSMENT OF FUTURE IMPACT 130 5.1 Kinetic Research Accident Environment Simulation and Projection Model 130 5.2 Approach 135 5.3 Assessment of Safety Impact of Design Change Vehicles 142 5.4 Further Analysis Considerations 147 5.5 Factor Considerations 152 5.6 Additional Considerations 153 TABLE OF CONTENTS (continued) SECTION TITLE PAGE 6 SUMMARY... 155 6.1 General Observations 155 6.2 Identification of Design Changes 157 6.3 Calculations of Observed Fatality Rate 158 6.4 Relationship of Observed Fatality Rate to Design Parameters 160 6.5 Assessment of Future Impact.. 162 7 CONCLUSIONS. 165 8 RECOMMENDATIONS. 167 REFERENCES. 169 LIST OF ILLUSTRATIONS FIGURE TITLE PAGE 2-1 Frequency Distribution over Curb Weight 1974-1977.. 29 2-2 Frequency Distribution over Wheelbase 1974-1977.... 30 2-3 Frequency Distribution over Width 1974-1977 31 2-4 Frequency Distribution over Length 1974-1977 32 2-5 Frequency Distribution over Height 1974-1977 33 2-6 Frequency Distribution over Roominess 1974-1977.... 34 2-7 Frequency Distribution over Rear Overhang 1974-1977 35 2-8 Frequency Distribution over Front Crush Length 1974-1977 36 2-9 Frequency Distribution over Body Side Thickness 1974-1977 37 2-10 Average Curb Weight in Roominess Class 1974-1977... 38 2-11 Average Wheelbase in Roominess Class 1974-1977 39 2-12 Average Width in Roominess Class 1974-1977 . 40 2-13 Average Length in Roominess Class 1974-1977 41 2-14 Average Height in Roominess Class 1974-1977 42 2-15 Average Roominess in Roominess Class 1974-1977..... 43 2-16 Average Rear Overhang in Roominess Class 1974-1977. 44 2-17 Average Front Crush Length in Roominess 1974-1977.. 45 2-18 Average Body Side Thickness in Roominess Class 1974-1977... 46 iv LIST OF ILLUSTRATIONS (Continued) FIGURE TITLE PAGE 3-1 Three Estimates Of Annual Vehicle Miles Traveled As A Function Of Vehicle Age 62 3-2 Monthly Mileage By Vehicle Age (Average Of Three Sources) 66 3-3 Monthly Mileage By Vehicle Age (HSRC) 67 3-4 Number Of Fatalities In 1977 By Model Year 71 3-5 Number Of Cars Registered in 1977 By Model Year .... 72 3-6 A Comparison Between The Proportions Of NCSS Accidents And The Adjusted Exposure Index For Fifteen Model Years 75 3-7 A Comparison Between NCSS Mileage Figures And The Mileage Data Unused In The Exposure Index 76 3-8 A Comparison Between NCSS Accident Proportions And HSRC- Based Exposure Proportions For The Two Model Year Periods Separated by FMVSS #215 77 3-9 Observed Fatality Rate Using Average Mileage Data . 79 3-10 Observed Fatality Rate Using HSRC Mileage Data 80 3-11 Number Of 1977 Passenger Car Fatalities By Impact Mode 83 3-12 Observed Fatality Rate By Impact Mode Using HSRC Mileage 84 3-13 Observed Fatality Rate By Impact Mode Using Average Mileage 85 3-14 The Proportion Of NCSS Accidents Within Each Of Fifteen Model Years Distributed By Five Impact Modes 87 3-15 A Comparison Between The Proportions Of NCSS Accidents And The Adjusted Exposure Index For Fifteen Model Years 88 3-16 A Comparison Between NCSS Accident Proportions And HSRC-Based Exposure Proportions For The Two Model Year Periods Separated BY FMVSS # 215 90 3-17 The Proportion Of The Total NCSS Accidents For Each Model Year, With Contributions By Impact Mode ... 91 3-18 Comparison Between Proportions Of NCSS Front And Rear Accidents And Exposure Proportions 92 3-19 Comparison Between Proportions Of NCSS Front And Rear Accidents And Exposure Proportions For The Two Model Year Periods Separated By FMVSS #215 ... 93 3-20 Comparison Between Proportions Of NCSS Side Accidents And Exposure Proportions 94 v LIST OF ILLUSTRATIONS (continued) FIGURE TITLE PAGE 3-21 Comparison Between Proportions Of NCSS Side Accidents and Exposure Proportions For The Two Model Year Periods Separated By FMVSS #215 95 3-22 Comparison Between Proportions Of NCSS Frontal Accidents And Exposure Proportions 96 3-23 Comparison Between Proportions Of NCSS Frontal Accidents And Exposure Proportions For The Two Model Year Periods Separated BY FMVSS #215 ...... 97 3-24 Comparison Between Proportions of NCSS Rear Accidents And Exposure Proportions 98 3-25 Comparison Between Proportions Of NCSS Rear Accidents And Exposure Proportions For The Two Year Model Year Period Separated BY FMVSS #215 . 99 3-26 Observed Fatality Rate In All Impact Modes 1974-1977 Passenger Cars In 1976 and 1977 FARS 105 3-27 Observed Fatality Rate In Front Impact Mode 1974- 1977 Passenger Cars in 1976 and 1977 FARS 106 3-28 Observed Fatality Rate In Side Impact Mode 1974-1977 Passenger Cars in 1976 and 1977 FARS 107 3-29 Observed Fatality Rate In Rear Impact Mode 1974-1977 Passenger Cars In 1976 and 1977 FARS 108 3-30 Observed Fatality Rate In Rollover Accidents 1974- 1977 Passenger Cars in 1976 and 1977 FARS ....... 109 3-31 Observed Fatality Rate Where The Victim Is Totally Ejected 1974-1977 Passenger Cars in 1976 and 1977 FARS 110 3-32 Observed Fatality Rate In All Impact Modes 1974-1977 Passenger Cars in 1976 and 1977 FARS Ill 3-33 Observed Fatality Rate In All Impact Modes 1974-1977 Passenger Cars in 1976 and 1977 FARS 112 5-1 Overview of the KRAESP Model .