The Traffic Accident Reconstruction Origin -Reference Library-

TARO Technical Articles

• A Business Analysis - The Feasibility of a Solo Practice in Traffic Accident Reconstruction A well trained and experienced police officer ponders leaving public service and working as a private consultant. What skills are important? Does he have the necessary background? Will he be successful? These questions are addressed in an MBA thesis by Denise Aquilante Johnson

• Sines and Cosines in Momentum Applications: What They Are and Why we Use Them Just what does W2V2 = W2V3 sin(theta) mean? Joe Cofone explains how we arrive at these terms and just what they mean. These expressions have real, graphic meaning.

• An Introduction to Train Brakes Ponder the amount of energy that an ordinary freight trains possesses as it rolls down the tracks at 70 M/H. Trains carry enormous amounts of cargo at great speed on a daily basis. The brake systems of a freight train is examined in this introductory article by John Bentley

• Automotive Black Box Data Recovery Systems Black Boxes are commonly used to aid the investigators of air crashes. Do automobiles have the equivalent of a black box? Is the data accessible to a collision investigator? Don Gillman explains one such system, its capabilities and limitations.

• Aerial Photography: Applications In Accident Reconstruction The value of aerial photographs as large exhibits is obvious. They are large and difficult to ignore. But aerials are more than just an exhibit. The utility of a "vertical aerial" is explored by Bob Wyman and Ross Cobb.

• An Examination Guide for Determining Seatbelt Use During a Collision Ed Phillips offers a strategy for determining seatbelt use during a collision. This article has many good ideas and some excellent photos of conclusive evidence.

• Injury Mitigation Devices This well illustrated article is a good introduction to the topic of seat belts. Basic seat belt concepts, an explanation of how they function, and terminology are covered in this submission by Ed Phillips

• Understanding the Vericom VC-2000 Accelerometer - Making Comparisons To Other Drag Factor Determination Methods Ed Livesay offers insight into the VC-2000. This article offers details on how it works, operational pitfalls, and comparisons to other drag factor testing devices.

• Sensitivity to Uncertainty Reconstructionists routinely measure some variable, plug it into an equation and solve for some unknown. Was the measurement exact?. Of course not. It had some error. The amount of error is called uncertainty. How uncertainty affects a result calculated in an equation is explored in this article by Dr. Oren Masory and Bill Wright.

• Error Analysis for Three Different Methods Of Determining Drag Factor Three different methods for determining drag factor are examined from an error analysis perspective. Depending on methodology, there is great variability in the resulting numbers. This article offers the step by step calculations for determining error in Skid Tests, Drag Sled tests and Accelerometer equipped vehicles. Dr. Oren Masory and Bill Wright.

• TAR Library List UPDATED 7/98 A reconstructionist spends a lifetime building a library of reference material. This list compiles standard works that would likely be included in just such a complete library. Please take the time to add your favorites to this list. The list was compiled by R.W. Bob Rivers.

• Solving Second-Degree and Systems of Equations: Applications to Motor Vehicle Accident Reconstruction Equations that have one unknown are very straightforward to solve. In that case, the knowns are substituted, the numbers are crunched, and the answer appears on the face of the calculator. An equation with more than one unknown quantities requires a different approach. A background and TAR example of this situation is explored in an article by Andrew Rich

• Three Point Airborne Trajectory Analysis When all the information is available airborne equations are capable of returning speed estimates of a fine tolerance. Unfortunately an investigator is usually not able to collect all the information necessary for these calculations. As a result he is forced to use an airborne equation to range estimates, or seek a minimum estimate. Andrew Rich offers an approach to make fine tolerance speed estimates from an otherwise incompatible situation.

• Pedestrian Accident Reconstruction: Review and Update This article offers a broad overview of pedestrian accident reconstruction. A background, terminology, and many methods of analysis are presented by Luis Martinez.

• Proposed Extensions to Federally Mandated Bumper Testing Hundreds of Federally Mandated Bumper Tests have been conducted. The tests are conducted with a rigid wall or impactor. This paper proposes methods by which the existing tests could be extended to yield additional design and analysis data that could be used to help design lower vehicle compartment loadings. Dr. Irving O. Ojalvo and Dr. Orem Masory

• The Importance of the Weight Distribution of a Vehicle During Braking It is common practice to assign static weight distributions to work done by a skidding tire. If one front tire carries 30 % of the vehicles weight at rest, that skidding tire must do 30% of the work while skidding right? Not necessarily. This question is explored by Dr Bruno Schmidt.

• Drag Factors at Different Speeds for Wet and Dry Concrete Is drag Factor speed dependent? This article details a series of skid tests that were conducted on wet and dry concrete to answer this question. Mike Sunseri and Bruno Schmidt

• Deriving the Critical Speed Equation- A Practical Example The Critical Speed model is valuable tool for speed estimates. This article offers a practical experiment to ground the concept behind the underlying principle. Bill Wright

• TAR Library List A reconstructionist spends a lifetime building a library of reference material. This list compiles standard works that would likely be included in just such a complete library. The list was compiled by R.W. Bob Rivers.

• Least Squares Method of Line Fitting Experiments are usually conducted find or validate mathematical models. These models are used to find unknown quantities in applied problems or predict future test results. The Least Squares method of line fitting is a way of developing mathematical expressions from experimental data. This procedure is explained and demonstrated in an article by Dr. Bruno Schmidt

• Using NHTSA's new Crash Test Data base NHTSA has updated the capabilities of its WWW crash test database. Jim Mitchell offers suggestions for accessing this information.

• Accessing NHTSA's Crash Test Database NHTSA has crash tested thouands of vehicles. Where is the data? It is here online, if you know how to access it. In a web "how to" article Tom Langley explains the procedure to get at this wealth of information.

• Evidence of ABS Scuffmarks on the Roadway. A group of South Florida accident investigators conduct an ABS workshop.Skidmarks and ABS scuff marks are generated on various surfaces, then examined, to develop a strategy for finding this evidence at future collision sites. This article contains additional documentation and previously unpublished photos. Bill Wright

• Vestigios de Frenagem Produzidos por Freios ABS Translation is by Raphael Martello

  This is a Portugese translation and technical adaptation of a TARO article that details the Evidence of ABS Scuffmarks on the Roadway. Are you bi-lingual? TARO will gladly make space available for translations of this and other Traffic Accident Reconstruction related articles.

• CARP 1.04 Computerized Accident Reconstruction Programs Where did all the DOS based 80286 computers go? Many are still out there languishing for software. J.F. Mitchell makes his original program CARP 1.04 available for free. This metric program includes basic and advanced Accident Investigation formulae.

• Stiff1: Stiff1 is a small downloadable Windows compatible program. Give the program barrier crash data and it computes the stiffness constants. James Perry

• iCAR V 2.4: iCAR is a comprehensive menu-driven traffic accident reconstruction application. It performs the calculations necessary for most reconstructions. iCAR is offered, free of charge, by its author James Perry

• Basic Accident Investigation Manual Many TARO readers are involved in accident investigation training. This is an accident investigation training manual that covers all basic AI topics. It is offered to the public domain by its author Luis Martinez.

• Private Practice, Law Enforcement and Traffic Accident Reconstruction: Two Perspectives Much has been said about the two most popular routes to a traffic accident reconstruction career. This article explores the benefits, drawbacks and differences in these two approaches.Wade Bartlett and Bill Wright

• Estimating Vault Distance and Speed After a Motorcyclist or Bicyclist Ejection This article offers a method of speed and trajectory analysis for collisions involving bicycles and motorcycles. Andrew Rich

• Update on the Motorcyclist / Bicyclist Equation This article extends the methods offered in Estimating Vault Distance and Speed After a Motorcyclist or Bicyclist Ejection to cover impacts involving pedestrians. A second derivation in more basic units is offered. Andrew Rich

• Measuring a Drag Factor with the Vericom VC 2000 The use and procedure for drag factor testing with the Vericom VC 2000 is explored in this article by Joseph Cofone

• Measuring a Drag Factor with the g-Analyst A discussion on friction testing methodology with the g-Analyst. B Wright

• Looking at Airbag Activation Sensors Ed Phillips offers an overview of some common airbag activation sensors.

• Renfroe Engineering Technical Papers David A. Renfroe and his firm, Renfroe Engineering, is a significant source of vehicle dynamics, off road vehicle, and occupant restraint research and publishing. The Renfroe website offers several related techinical papers.
  • An Overview of Emergency Locking Retractor Performances of Shoulder Harness Safety Belt Systems in American Made Vehicles
  • Modeling of Vehicle Rollover and Evaluation of Occupant Injury Potential Using MADYMO
  • Simulation of a 3-Wheeled All Terrain Vehicle (ATV)Transient and Steady-State Handling Characteristics

• Speed From Skids: A Modern Approach This full 'net reproduction of SAE 950354 discusses modifications to the basic "Speed from Skid mark" equation. The kernel in this different approach centers on estimating work done by braking tires prior to the point visible skid marks are observed. This article is in Adobe Acrobat format (Get Adobe Acrobat Reader) . It is authored by James Neptune, James Flynn, Philip Chavez and Howard Underwood.

• A Method for Quantifying Vehicle Crush Coefficients This 1992 paper offers a method for calculating vehicle crush coefficients from NHTSA Vehicle Crash Test Data Base. Of course this data-base is now available online. Though now several years old this paper offers a excellent history of speed from crush concepts. This article is in Adobe Acrobat format. James Neptune, George Blair, James Flynn

• Road Accident Research Unit The University of Adelaide This site offers an online search capability of the RARU Library Catalogue. Though you may not live close enough to Adelaide to check out a volume, this search capability will certainly get you started in your local university library.
  

• Canadian Vehicle Specification System (CVS) Version 1998.1 UPDATED from 2000.1 CVS is a free vehicle specification program. It is made available by Dr. Alan German at Jim Mitchell's website. (Note: this program is set to open giving specifications in metric units. English units are available via F keys).

• On-line Mathematics Dictionary Mathpro's brief Mathematics Dictionary. This page also has links to the Mathpro On-line glossary of technical notation.

• IUN/FYDE Introductory Physics Notes These WWW pages constitute a general, non-calculus introductory physics course. They are based on lectures given through the IUN/FYDE distance education program of the University of Winnipeg.
  

• Temporary Brake Failure, It is Possible? Would you believe a person that told you his brakes failed causing a collision when they work well in a post collision inspection? A technical paper discusses this issue.Wade Bartlett
  

• Critique of Rudy Limpert's Book Brake Design and Safety Author Wade Bartlett reviews of the first 100 pages of Mr. Limpert's book and finds many numerical errors, and editorial complaints. If you own the book this critical review should be close by.

• A Technical Review of Northwestern University's Topic 823: Lamp Examination for ON or OFF in Traffic Accidents Frederick G. Hochgraf reviews this manual and finds some statements which are incorrect and/or misleading that can lead an investigator to incorrect conclusions. Print this review and place it in the volume.

• Vector Momentum Analysis An excellent introduction and discussion on momentum collision analysis. The article has many illustrations and much support for a graphic understanding of momentum. George M. Bonnett

• Collision Times Four A simple "thought experiment" sheds light on the relationship between energy, work, and momentum. Understand this example and it will serve you as a convenient reminder for the rest of your life. George M. Bonnett

• ACTAR ACTAR is online. Of interest are its history, the ACTAR Newsletter and CEU information.

• Compute A Crash Ed Livesay offers an original piece of accident reconstruction software. It is well written and offers much in the way of user support and error checking.

• Canadian Vehicle Specification System (CVS) Version 1996.2 CVS is a free vehicle specification program. It is made available by Dr. Alan German at Jim Mitchell's website. (Note: this program is set to open giving specifications in metric units. English units are available via F keys).

• Human Error in Road Accidents: An Information Processing Analysis This article provides a brief overview of human information processing limitations and explains how they can contribute to road accidents. This is a "first-principles" approach to accident investigation because it draws on knowledge of basic human psychological processes. Instead of looking at the driver from the outside, we try to understand his/her mental processing and how it interacts with the environment. Marc Green, Ph.D. John W. Senders, Ph. D

• Anti-Lock Brakes - What they can and cannot do.This article explores ABS, how it works, when it works, and when it doesn't. James Harris.

• Lamp Examination to Determine On or Off Condition in a Collision : Many times the condition of a lamp can be important in the analysis of a collision. This article details the general methods involved in lamp analysis. It is an excelent introduction to the topic. James Harris

• Human Factors - Memory in Accident Reconstruction: Frequently Accident investigators are offered witness statements. How reliable are they? How can witnesses contradict physical evidence? These topics are explored in an essay by Joseph E. Badger.

• Human Factors - Perception & Reaction : How reliably can a reconstructionist estimate a reaction time? What about the calculations based on this reaction time? Is reaction time influenced by the time of day or available light? These and other factors are examined in an article by Joseph E. Badger.

• SMAC-97 Refinement of the Collision Algorithm "This page is the text of the presentation on February 27, 1997 by Brian G. McHenry of the paper "SMAC-97 - Refinement of the Collision Algorithm", SAE Paper 97-0947". Does a computer model always fit? Do we know when it doesn't? Brian McHenry

• University of Michigan Engineering Research Division public domain software site. The University of Michigan's Engineering Research Division offers some free accident investigation software.

• Torque and Horsepower - A Primer This is a common experience essay, in hot rod terms, on the difference between power and torque. Fundamental units are lightly treated. Bruce Augenstein

• The Effects of Grade on Kinetic Friction Accident investigators routinely adjust level friction values with the tangent (slope) of the angle traveled by the sliding vehicle. Is this a valid adjustment? The relationship is derived in a technical paper at REC-TEC's site.George M Bonnett, J.D.
  

• Understanding Delta V from Damage A introduction, history and discussion of crush and why it is important to the accident investigator. The article contains numerous charts, illustrations and graphs.George M Bonnett, J.D.
  

• Bowling's Automotive Programs A grab bag of online java scripts for the automotively bent engineer. Of specific interest is a routine that calculates a tire's effective rolling diameter and another that finds engine R/M from M/H.Algorithms are offered for most routines.Bruce Bowling

• Manual of Traffic Signs Richard Moeur is a engineer with the Arizona Departmant of Transportation. His web page offers general observations on the subject of Traffic Control Devices. Contained in other portions of this page are a good representation of a Traffic Engineer's Ramblings.

• Fedworld The "top" of US Federal Government WWW resources. The following pages are currently available by searching down Fedworld links.

• United States Department of Transportation Of interest is an Organization Chart of all DOT resources.The highest order Catagories are:
  • What's New
  • Help and DOT web search
  • DOT Home Page
    • DOT Administrations
    • Office of the Secretary
    • Office of the Inspector General
    • Transportation Administrative Service Center
    • Federal Aviation Administration
      • N T S B Aviation Accidents NTSB aviation investigations occasionally get intense media coverage. These major incidents represent only a small part of their workload. This page links down to summarys of 37,000 investigations they have conducted since 1983. These reports are an interesting perspective for the reconstructionist.

    • Federal Highway Administration
      • Manual on Uniform Traffic Control Devices (MUTCD)- Revisions and Rewrites The Federal Highway Administration offers Revisions and Rewrites and Reformats to the Manual on Uniform Traffic Control Devices (MUTCD) online. Documents are available as Text or Adobe Acrobat files. Be sure to use the pull down menus for access to the documents.

    • Federal Railroad Administration
    • Federal Transit Administration
    • National Highway Traffic Safety Administration
      • NHTSA FMVSS 208 and 214D FMVSS 208 Frontal Crash Test Data Sheets and FMVSS 214D Lateral Crash Test Data Sheets. NHTSA has upgraded its site to include this crash test occupant data. Tests from 1987 through present are offered.

      • NHTSA Compliance Test Procedures The Office of Vehicle Safety Compliance (OVSC) provides contracted laboratories with Laboratory Test Procedures (TPs) which serve as guidelines for obtaining compliance test data. The data are used to determine if a specific vehicle or item of motor vehicle equipment meets the minimum performance requirements of the subject Federal Motor Vehicle Safety Standard (FMVSS). This page offers some of these TPs.
        Note: Many of these procedures are only down loadable as a Word Perfect Document.

      • Chart of 1997 NHTSA OVSC Test Labs, locations, and contact information Locations and contact information for NHTSA testing labs.

      • NHTSA Office of Vehicle Safety Compliance (NSA-30) Organization Chart Names and phone numbers at NHTSA.

      • NHTSA Now The NHTSA newsletter.

      • A List of Recent Vehicle Recalls

      • NHTSA Traffic Safety Materials Catalog Get some of your tax dollars back with free pamphlets, videos and instructional materials. Orders can be placed 'online'.

      • NHTSA FTP files

      • Simple searchable indexes of:
        • Auto and Truck Recalls

        • Technical Service Bulletins.

        • Consumer Complaints.

        • Defect Investigations

    • Bureau of Transportation Statistics : BTS is an arm of the US Department of Transportation charged with "improving public awareness of the nation's transportation system and its consequences". This site offers a great deal of general transportation information, and is searchable.

    • DOT News and Press Releases
    • General Information

  • End of Department of Transportation Resources

• National Technical Information Service An index of available federally produced scientific, engineering and technical papers. First read the terms and conditions then search the data-base. Try using Automobile at the search prompt.

• The United States Naval Observatory : USNO is the official time keeper for the United States. This WWW page offers a accurate up to the second clock. It also offers an online calculator to display Sunrise and Sunset times for any location in the world.

• Code of Federal Regulations Online CFR capability includes search by keyword, search by cite, search by title, and related historical data.
  

• End of United States Federal Resources

• SAFER The Safety and Fitness Electronic Records (SAFER) System is planned as a component of Intelegent Transportation System. SAFER will provide carrier, vehicle, and driver safety and credential information to fixed and mobile roadside inspection stations. The FHWA Office of Motor Carriers has provided carrier safety data to industry and the public for many years via telephone requests and paper reports. The SAFER System makes it possible to offer this information electronically. Limited SAFER functions are now provided free of charge over the Internet.

• Sisters and Clones This Adobe Acrobat document has general vehicle information on most vehicles manufactured from 1980 to date. Included in this list is information on ABS availability, frame construction, drive axle, body styles, and "sister" vehicles offered by other companies under the same manufactuting parent company. This list is offered by George Scalia of Scalia Safety Engineering. It of offered free on the Neptune Engineering website.
  

• Euclid's Elements One of the five most popular books of all time. This website presents this foundation of science in a WWW java enhanced enviornment. The page is the work of D. E. Joyce

• Alignment Methods Author Mike Piera offers techniques for checking and adjusting automotive front end alignment. Though these adjustments are offered on a obscure car (Porsche 911), many of these same measurement methods are applicable to a first order post collision vehicle inspection.

• SAE: The Engineering Society for Advancing Mobility Land Sea Air and Space ® . The site features general information about the societiy's purpose, membership information and a calendar of events. A search capability accesses an impressive list of SAE technical papers.

• The Insurance Institute for Highway Safety: IIHS is a nonprofit, scientific, educational organization dedicated to reduction of losses on the highway. IIHS's current web page has a distinct consumer slant. The page has been online only a few months and offers a minimal search capability. IIHS now makes makes most of its publication Status Report available online.

• The Highway Loss Data Institute: HLDI is an organization supported by IIHS dedicated to publishing data on the way insurance losses vary by vehicle type. This site offers searchable access to the same IIHS database.

• Goodyear Tire and Rubber Company has a page that is primarily oriented toward the consumer. There is basic information available on chassis alignment, tire wear, tire sizing, and tire grading at the ISO 690-2, Bibliographic references to electronic documents A well defined standard exists for quoting a paper document in a bibliography. How do you quote an electronic document? This is the International Organization for Standardizations (ISO) current recomendation.

• Alldata: Alldata Corporation is the leading publisher of Electronic Automotive Diagnostic and Repair Information. The Alldata web site offers searchable access to Safety Recalls, General Recalls, and Technical Service Bulletins.

• Car and Driver : The print magazine Car and Driver has a WWW presence. Of interest to the reconstructionist is The Daily Insider. The Daily Insider reports on late-breaking automotive news. Also of interest the Buyers Guide offers basic vehicle information (wheelbase, track and weight) for many late model vehicles. To retrieve this information, search the vehicle in question then click on STATS at the bottom of the page.

• Popular Mechanics: This WWW magazine offers vehicle specifications on many new cars in the searchable New Car and Truck Buyers Guide.

• The Physics of Auto Racing. Frequently a car involved in a collision is operated at the limit of its performance envelope for a few seconds. Race cars operate at this limit on a continuous basis. In a series of articles, Brian Beckman explores the consequences of operating at the edge. These articles are an interesting perspective on the commonality of science. Auto racers and accident reconstructionists are really talking about the same thing. Brian Beckman.

• AutoWare AutoWare is a small software development company that produces racecar applications. Their web site contains some simple and short articles that should be of interest to the reconstuctionists. Among them are the following topics:
  • Slip Angles and Handling
  • Handling Troubleshooting Guide(tape method)
  • Toe-out and Handling
  • Ackerman and Racing

• The Interactive Textbook for 1996: This is a WWW college level physics class and texbook. The course includes lecture notes to assist in the understanding of topics presented in the text. This course is offered through the University of Pennsylvania. It is the work of Dennis DeTurck, Larry Gladney, and Anthony Pietrovito.

• Net Science Three exceptional High School students have put together a simple, short and easy to read 'online' Physics course. This course is a good place for the informally trained accident investigator to start. Its simplicity and fresh examples will also amuse the trained veteran. The few non-critical errors on these pages are worth overlooking.

• Glenbrook South High School "Physics Classroom" This is a particularly well executed online physics class. It is geared for a student without a calculus background. The page has many examples and interactive problems. The page is offered by Glenwood South High School in Glenwood, Illinois USA.

• Automotive Learning Online A particularly clever use of java scripts that teach basic concepts. Have you ever wondered just how spider gears allow a differential to drive axles at two different speeds? An animation here will demonstrate. This site is made available by Information Graphics Company.

• The Skeptical Inquirer: It is the business of accident reconstructionists to draw conclusions. A crucial part of this process should be "the critical look." The Skeptical Inquirer examines the fringes of popular science and applies this critical look. The topics are not accident reconstruction, but the process serves as a good model for a well considered conclusion.

• Yahoo's Government Index The Yahoo Search index of Web government resources. This index includes most of the Web pages contained in Fedworld, but also offers state Web resources. Many of these contain links down to county and city Web sites.

• The Internet Roadmap Still a little confused about just what the Internet is? This is a general overview of what's out there and how to use it. Patrick Crispen

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