CONTENTS 1 Introduction 1 1.1 Background 1 1.2 Objective 1 1.3 Scope 2 1.4 Report Organization 3 2 Literature Review 4 2.1 In-Depth Crash Data Collection 8 2.2 Impact Conditions of Ran-off-Road Crashes 8 2,3 Data Needs for Study of Ran-off-Road Crashes 8 2.4 Reconstruction of Ran-off-Road Crashes 9 3 Study Approach 10 3.1 General 10 3.2 Data Needs 10 3.3 Data Collection Alternatives 10 3.4 Data Collection Protocol 13 3.5 Data from Previous Studies 23 3.6 Relational Database 25 4 Results 26 4.1 General 26 4.2 Descriptive Statistics 26 4.3 Departure Conditions 32 4.4 Impact Conditions 39 4.5 Encroachment Length 48 4,6 Significance for Guardrail Runout Length 52 5 Long-term Data Collection Plan 55 5.1 General 55 5.2 Data Collection Alternatives 56 5.3 Proposed Data Collection Plan 56 5.4 Pilot Study 58 5.5 Data Collection Protocol-Continuous Sampling Subsystem 62 5.6 Data Collection Protocol-Special Studies Subsystem 63 5.7 Summary 64 6 Summary of Findings 65 6.1 Study Approach 65 6.2 Findings 65 6,3 Long-Term Data Collection 65 References 67 Appendices 69