The manual provides an introduction to traffic accident investigation and describes the series of events associated with a traffic accident that an investigator should know about. The manual also covers investigation procedures, the human element, questioning drivers and witnesses, environmental factors, highway and vehicle marks and damages, vehicle mechanical inspection, photography, failure to remain at the scene of a traffic accident, and speed estimates. In addition, the manual contains guidance on how to prepare field sketches, maps, and diagrams of the traffic accident scene. Appendixes contain further procedural information on traffic accident investigation. References, tables, and figures