This textbook edition is a collection of the most important techniques and definitions essential for developing an accurate picture of motor vehicle collisions. This textbook is intended to aid investigators by providing them with necessary techniques for collecting information to save lives and reduce monetary losses due to automobile collisions. It is the culmination of 73 years of progressive development of a body of information on systematic traffic-accident investigation. The book contains multiple illustrations, diagrams, and sketches showing the various aspects of data collection and interpretation. The information collected in a collision investigation is used by administrators to make the highway transportation system safer, as data show that motor vehicle collisions kill more Americans between the ages of 1 and 19 than any other cause. This book contains 11 chapters covering the subjects of preparation for traffic collision investigation, information from and about people, information from vehicles, information from roads, measuring and mapping the collision scene, photographing the collision scene and damaged vehicles, lamp examination for "on" or "off" in vehicle collisions, tire examination after motor vehicle collisions, photogrammetry for collision analysis, understanding vehicle behavior in collisions, and highway/rail grade crossing collision investigation. In conclusion, it is noted that this book will contribute to the improvement of the investigation of motor vehicle related collisions, the prosecution and defense of those related to such events, and the protection of the public welfare.