Contents
1. Introduction 8
1.1. Study Objectives 8
1.2. Study Characteristics 9
1.3. Background 10
1.3.1. Crash Data 10
1.3.2. 1981 Survey on Unreported Crashes 11
1.3.3. Additional Research 13
2. Methodology 14
2.1. Sample Design 14
2.1.1. Landline Sampling 14
2.1.2. Cell Phone Sampling 14
2.2. Data Collection 14
2.2.1. Questionnaire Development 14
2.2.2. Interviewer Training 19
2.2.3. Data Collection Schedule 19
2.3. Response Rates 19
2.3.1. Distribution of Household Cases by American Association of Public Opinion Research (AAPOR) Category 19
3. Results 22
3.1. Reporting Status of Crashes by Crash Type 23
3.1.1. Crashes Reported and Unreported to Police 23
3.1.2. Crashes with Known Reported to Police Status by Crash Type 25
3.1.3. Crashes Reported and Unreported to Insurance 27
3.2. Incidence of Reported and Unreported Motor Vehicle Crashes 29
3.3. Vehicle Damage Associated with Unreported and Reported Crashes 30
3.4. Injuries Associated with Unreported and Reported Crashes 32
3.4.1. Injuries That Require Treatment 32
3.4.2. Where Injuries are Treated 32
3.4.3. Injuries That Require Hospitalization 34
3.4.4. Days Lost to Normal Activities 34
3.4.5. Medical Costs 35
3.4.6. Types of Injuries 36
3.5. Reasons That Crashes are Unreported 42
3.6. Circumstances Surrounding Unreported and Reported Crashes 46
3.6.1. Number of Other Vehicles Involved 46
3.6.2. Vehicle Area Damaged 48
3.6.3. Crash Location 50
3.7. Demographic Factors 52
3.7.1. Gender 52
3.7.2. Age 52
3.7.3. Race 52
3.7.4. Education 53
3.7.5. Income 53
4. Discussion 54
4.1. Major Findings 54
4.2. Limitations 55
5. Conclusions 57
References 58
APPENDIX A. Landline Questionnaire 60
APPENDIX B. CELL PHONE SURVEY 86
APPENDIX C. FREQUENCIES 113
Table 1.3.1/Table 1.3.2. Comparisons of the Greenblatt 1981 Survey to Current Survey 12
Table 2.1. Sample allocation for the National Survey on Reported and Unreported Motor Vehicle Crashes 14
Table 2.2a/Table 2.3a. Distribution of Household Cases by AAPOR Category 20
Table 3.1.1a. Percentage of crashes by reported to police, unreported to police, and unknown reported to police status for all crashes and for each injury and vehicle damage only category. 24
Table 3.1.1b. Weighted number of crashes by reported to police, unreported to police, and unknown reported to police status for all crashes and for each injury and vehicle damage only category. 24
Table 3.1.2a. Percentage breakdown of all crashes with known reported to police status by injury and vehicle damage only category. 25
Table 3.1.2b. Percentage breakdown of reported crashes with known reported to police status by injury and vehicle damage only category. 26
Table 3.1.2c. Percentage breakdown of unreported crashes with known reported to police status by injury and vehicle damage only category. 26
Table 3.1.3a. Percentage of crashes by reported to insurance, unreported to insurance, and unknown reported to insurance status for all crashes and for each injury and vehicle damage only category. 27
Table 3.1.3b. Weighted number of crashes by reported to insurance, unreported to insurance, and unknown reported to insurance status for all crashes and for each injury and vehicle damage only category. 28
Table 3.2a. Weighted percentages of all crashes reported to the police, reported to the insurance company, reported to both, and reported to neither. Base = 2,158 crashes with known reported to police status... 29
Table 3.2b. Weighted percentages of vehicle damage only crashes reported to the police, reported to the insurance company, reported to both, and reported to neither. Base = 1,652 crashes... 30
Table 3.2c. Weighted percentages of injury crashes reported to the police, reported to the insurance company, reported to both, and reported to neither. Base = 506 crashes with known reported to police status... 30
Table 3.3a. Vehicle repair costs for all crashes, damage only crashes, and injury crashes, segregated by reported or unreported to police. 31
Table 3.3b. Vehicle repair costs as above, only segregated by reported or unreported to Insurance 31
Table 3.4. The distribution of the number of people injured in all crashes, reported crashes, and unreported crashes. 32
Table 3.4.1a/Table 3.4.2a. Number and percentage of injured respondents treated at each location, for all crashes. 33
Table 3.4.1b/Table 3.4.2b. Number and percentage of injured respondents treated at each location, for reported crashes. 33
Table 3.4.1c/Table 3.4.2c. Number and percentage of injured respondents treated at each location, for unreported crashes. 33
Table 3.4.2/Table 3.4.3. The number and percentage of respondents who required hospitalization overnight or longer as a result of the injuries suffered in the crash. 34
Table 3.4.3/Table 3.4.4. The distribution of the number of days lost to normal activities, such as work or school, as a result of injuries suffered in the crash. 35
Table 3.4.4/Table 3.4.5. The distribution of medical costs for all crashes and for reported and unreported crashes separately. 36
Table 3.4.5a/Table 3.4.6a. The distribution, over all crashes, of the most serious injury suffered by the respondent. 37
Table 3.4.5b/Table 3.4.6b. The distribution, over reported crashes, of the most serious injury suffered by the respondent. 38
Table 3.4.5c/Table 3.4.6c. The distribution, over unreported crashes, of the most serious injury suffered by the respondent. 39
Table 3.4.5d/Table 3.4.6d. The distribution, over all crashes, of the most serious injury suffered by a person other than the respondent. 40
Table 3.4.5e/Table 3.4.6e. The distribution, over reported crashes, of the most serious injury suffered by a person other than the respondent. 41
Table 3.4.5f/Table 3.4.6f. The distribution, over unreported crashes, of the most serious injury suffered by a person other than the respondent. 42
Table 3.5a. The distribution of the reasons given for not reporting an injury crash to the police. 43
Table 3.5b. The distribution of the reasons given for not reporting a vehicle damage only crash to the police. 44
Table 3.5c. The distribution of the reasons given for not reporting a crash to the police, all crashes combined. 45
Table 3.6.1a. The distribution of the number of other vehicles involved in the crash for all injury crashes. 46
Table 3.6.1b. The distribution of the number of other vehicles involved in the crash for reported injury crashes. 46
Table 3.6.1c. The distribution of the number of other vehicles involved in the crash for unreported injury crashes. 47
Table 3.6.1d. The distribution of the number of other vehicles involved in the crash for all vehicle damage only crashes. 47
Table 3.6.1e. The distribution of the number of other vehicles involved in the crash for reported vehicle damage only crashes. 47
Table 3.6.1f. The distribution of the number of other vehicles involved in the crash for unreported vehicle damage only crashes. 48
Table 3.6.2a. The distribution of the vehicle area damaged in the crash for all injury crashes. 48
Table 3.6.2b. The distribution of the vehicle area damaged in the crash for reported injury crashes. 49
Table 3.6.2c. The distribution of the vehicle area damaged in the crash for unreported injury crashes. 49
Table 3.6.2d. The distribution of the vehicle area damaged in the crash for all damage only crashes. 49
Table 3.6.2e. The distribution of the vehicle area damaged in the crash for reported damage only crashes. 50
Table 3.6.2f. The distribution of the vehicle area damaged in the crash for unreported damage only crashes. 50
Table 3.6.3a. The distribution of crash location for all injury crashes. 50
Table 3.6.3b. The distribution of crash location for reported injury crashes. 51
Table 3.6.3c. The distribution of crash location for unreported injury crashes. 51
Table 3.6.3d. The distribution of crash location for all damage only crashes. 51
Table 3.6.3e. The distribution of crash location for reported damage only crashes. 51
Table 3.6.3f. The distribution of crash location for unreported damage only crashes. 52