Abstract
Multi-level system of accident investigation is recommended. This system is designed to provide accident records that propriate in both quantity and quality for the specific tanks or which the data are intended. The suggested three levels of investigative effort are: 1. Basic reporting of all reportable accidents; 2. Limited investigation of a sample of accidents for selected research objectives on special topics; 3. Intensive investigation of a limited number of accidents plioit in the proposed system in the need to integrated accident data with the appropriate non-accident data-driver, bicycle and highway records.