Goodies for the Reconstructionist's Library

Article excerpt

The closest thing you're going to get to an accident reconstruction encyclopedia is the new "Anatomy of the Collision: Energy, Momentum, Restitution and the Reconstructionist" by George M. Bonnett (IPTM, Jacksonville, 1999).

Over the years Bonnett has expostulated extemporaneously on subjects ranging from the "Effect of Kinetic Friction" to "Conservation of Momentum" and "Calculating PDOF Angles." He composed an unpublished essay on the "Effect of Grade on Kinetic Friction" early in the last decade. Six years later he discussed determining drag factors with different types of sleds, electronic accelerometers, and so forth in "The Airborne Drag Factor."

He also wrote an essay, "Understanding Delta V from Damage," that was never published, but rather just sort of languished in the personal libraries of his associates. But it seems now that enough people finally persuaded him to compile his sundry miscellany into one work for the world to see.

In his latest book, the title chapter, "Anatomy of the Collision: Variations on a Theme," and a related workbook chapter make up the first 95 pages of the 227-page book.

Bonnett dissertates details of eight collisions that include 44 variants that represent an overview of "the Conservation of Energy and Momentum and the mechanics of Restitution as applied to vehicular collisions."

Bonnett's book also addresses Vector Momentum, Measuring Linear Momentum Angles, Simultaneous Linear and Angular Deceleration, Uniform Circular Motion and Inertia, and Deceleration in a Yaw. He includes an intriguing thesis on the Secondary SlapTwo Collisions or One?

The book isn't an instruction manual on how to investigate or reconstruct traffic crashes (you should already know how to do those tasks before getting this book), but rather a way to fine-tune your expertise. Be warned, however: "Anatomy of the Collision: Energy, Momentum, Restitution and the Reconstructionist" is not the easiest book to read. It may require two readings-once to get a taste, a second time to savor the flavor. And on your second read, consider having a scientific calculator close by.

While the book has no pictures, Bonnett uses graphics from his RECTEC computer software to illustrate as he deliberates. He would probably want me to mention that he writes of a "new and innovative restitution calculation and a unique and simple approach to calculating both the maximum damage energy as well as the actual energy available for damage and rotation." These are in the Conservation of Linear Momentum section.

The publisher strayed from its usual spiral comb or 19-ring binding and did Bonnett's book in "perfect binding," making it more like a "real" book than a simple published treatise.

Cost of the book is $40.00 (plus $4.50 shipping and handling). To order or for information about IPTM publications, contact the Publication Department, IPTM, University of North Florida, 12000 Alumni Drive, Jacksonville, FL 32224 or call 904.620.4786 or visit their web site:

A revision of R.W. (Bob) Rivers' book, "Traffic Accident Investigators' and Reconstructionists' Book of Formulae and Tables," is also available. The handbook, Publisher Charles C. Thomas said, "is prepared for the daily, practical needs of those who are involved in traffic accident analysis, investigation, and reconstruction, whether they be in the training, police, private, or legal professions.

"Many tables and constants relating to English (U.S.) and metric (S.L) systems are provided," he continued, "so that those who may normally work under one system but use reference materials in the other will have a readily accessible means of making any necessary conversions." (For U.S. readers, "S.L" comes from the French "Le Systeme International d'Unites" and is used by most countries outside the United States. It's their way of saying "metric.")

For those who already have the first edition of Rivers' book, this is a completely new publication, a new approach to a book of formulae and tables. …