Development of roadside safety data collection plan

The purpose of this study is to support the roadside aspect of the FHWA High Priority National Research Area on Highway Safety Design Practices and Criteria. The objectives of this study are to: (1) identify issues and gaps in the state of the knowledge needed to improve the costeffectiveness analysis procedure, to be developed under NCHRP Project 22-9, Improved Procedures for Cost-Effectiveness Analysis of Roadside Safety Features, and (2) develop data collection plans for those issues and gaps that can be addressed with accident data. A conceptual framework of the cost-effectiveness model was first formulated. A list of research topics that could potentially improve the cost-effectiveness model was identified. Five proposed research studies were developed from the list: (1) Validation of Encroachment Frequency/Rate, (2) Determination of Encroachment Frequency/Rate Adjustment Factors, (3) Effect of Roadside Conditions on Impact Probability and Severity, (4) Distributions of Impact Conditions, and (5) Relationships of Impact Conditions, Performance Limits, and Injury Probability and Severity. Detailed data collection plans were developed for each of the five proposed studies. A 1-day meeting of an expert panel was convened to critically review these data collection plans. Also, a data collection plan for a combined proposed studies 1 and 2 was developed.