Commercial Vehicle Accident Reconstruction and Investigation [2 ed.] 9781933264837, 1933264837, 2010033382

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Commercial Vehicle Accident Reconstruction and Investigation Second Edition

Rick W. Varner ·Roy F. Sutphen, Sr.

•(:) 1® Lawyers & Judges ~ Publishing Company, Inc. Tucson, Arizona

This publication is designed to provide accurate and authoritative information in rega rd to the subject matter covered. It is sold wi th the understanding that the publisher is not engaged in rendering legal, accounting, or other professional service. If legal advice or other expert assistance is required, the services of a competen t professional person should be sought.

- From a Declaration of Principles jointly adopted by a Committee of the American Bar Associat ion and a Cornmi tlce of Publi shers and Associarions. The publisher, editors and authors mu st disclaim any liability. in whole or in part, arising from the information in this volume. The reader is 111rgcd to verify the reference material prior to any detrimental reliance thereupon. Since th is material deals with legal, medical and engineering information, the reader is urged to consult w ith an appropriate licensed professional prior to taking any action that might involve any interpretation or application of information within the realm of a licensed professional practi ce. Copyright © 201 1 by Lawyers & Judges Publi shing Co., Inc. All rights reserved. A ll chapters are the product of the Authors and do not reflect the opinions of the Publi sher. or of any other person, entity. or company. No pan of this book may be reproduced in any form or by any means. including photocopy, or electronic usc. without permission from the PubI isher's representati ve at the Copyright Clearance Center, I nc. (CCC) at www.copyright.com.

•G J$Lawyers & Judges ~

Publis hing Company, Inc.

P.O. Box 30040 • 1\tcson. AZ 85751 -0040 (800) 209-7109 • FAX (800) 330-8795 e-mail: [email protected] www. lawyersandjudges.com

L ibrary of Congress Cataloging-in-Publication Data Varner, Rick W. Commercial vehicle accident reconstruction and investigation I Rick Varner. Roy F. Sutphen, Sr. -- 2nd eel. p. cm. Rev. ed. of: Commercial vehic le accident reconstruction and investigation I Roy F. Sutphen. Sr. and Rick W. Varner. 2003. In carliercd. Roy F. Sutphen's name appeared fi rst. Includes bibliographical references and index. ISBN-13: 978-1-933264-83-7 (casebound : alk. paper) ISBN-10: 1-933264-83-7 (casebound : alk. paper) I . Traffic accident investigation. 2. Commercia l vehicles. I. Sutphen, Roy F. Commercial veh icle accident reconstruction and investigation. ll. Title. HV8079.55.S87 20 10 363.12'565--dc22 2010033382 Pri nted in the U nited States of America 1098765432 I

Contents Acknowledgments ........... ........................................ ..................... ..................... v Chapter 1: Introduction .................................... ............................................... 1 Chapter 2: 49 CFR!North American Out-of-Service Criteria .... .... ..... ......... 9 Chapter 3: Types of Carriers ......................................................................... 15 Chapter 4: Driver Responsibilities ...................... .............................. ............ 19 Chapter 5: Driver's Record of Duty Status ........... .... ............................... .... 25 Chapter 6: Commercial Driver's License Regulations ................................ 47 Chapter 7A: Electrical System .................................. .... ................................ 65 Chapter 7B: Lamp Overview .. ....................................................................... 75 Chapter 8: Wheels and Rims ......................................................................... 89 Chapter 9: Tires ......................................................... ..................................... 95 Chapter l OA: Fuel System and Exhaust System ........................................ 1J 5 Chapter lOB: Fire Case (Regeneration Filter) .......... ................................. 121 Chapter 11: Coupling Devices ....................... .............................................. 131 Chapter 12: Steering Components ............................ .................................. 141 Chapter 13: Terminology ............................................ .... .... ......................... 145 Chapter 14: Fundamentals of Compressed Air and Brakes ..................... 159 Chapter 15: The Brake System .................................................................... 165 Chapter 15A: Hydraulic Brake Systems......................................... .... .... .... 175 Chapter 158: Electric Brakes ...................................................................... J 79 Chapter 15C: Hydraulic Surge Brakes ....................................................... 185 Chapter 15D: Air Brake System Components ........................................... 187 Chapter lSE: Air over Hydraulic Brakes ........................................... ........ 2 11 Chapter 15F: Truck Retarder Systems....................................................... 213 Chapter 15G: The Wedge Brake System .................................................... 217 iii

iv

Commercial Vehicle Acc ident Reconstruction and Investigation

Chapter ISH: Brake Chapter Summa ry .................................................... 223 Chapter 16: Vehicle Inspection for Braking Efficiency........... ........ .......... 229 Chapter 17: Brake Balance a nd Timing .................................................... . 25 1 Chapter 18: Tra iler Design ................. ............ ............................................. 259 Chapter 19: Types of Trailers ................. .... .................. ............................... 265 Chapter 20: Trailer Underride a nd Rear-End Protection ........................ 273 Chapter 21: Loa d Securem ent. .. ..... ............................................................. 283 Chapter 22: Roadway Evidence .................................... ... ..... .... ..... ............. 287 Chapter 23: Vehicle Evidence .... .......... ........................................................ 299 Chapter 24: Human Factors ............ .............................. ... .. ......................... 3 17 Chapter 25: Off-Tracking ................................................... ......................... 339 Cha pter 26: Vehicle Dynamics ......................................... .. ........... .. ............ 345 Chapter 27: Commercial Vehicle Rollover................................................. 353 Chapter 28A: Automatic On-Board Recording Devices (AOBRD) ......... 369 Chapter 28B: ECM and Accident Reconstruction (The Caution Zone) ... 377 Chapter 28C: Wireless Communications Equipment ............................... 379 Cha pter 28D: Collision Warning Syste ms a nd Smart C ruise for Heavy Trucks .................................... .... ......... .... ..... .... ............. ......... ................. 38 1 Chapter 28E: Vehicle Speed Sensor ............................................................ 385 Chapter 28F: Questions that Can Be Asked During Testimony .............. 389 Chapter 28G : ECM Reliability and Concerns .................... .. ..................... 393 Chaptet· 28H: Terminology, Acronyms and Definitions for Electronic Data from ECMIECUIEDR .. ...... ..................... ............ ... ... .................. 397 Chapter 281: What Components Make a Computer? ............................... 40 1 C hapter 28.J: Commercial Vehicle Documents/Information for Analysis ...................... ......... ..... .... .. ................ ........................................ 403 Chapter 28K: ECM Data Chart ..................... ............................................. 405 Chapter 29: Other Speed Formulas .................. ..................... .. ................... 407 Appendix A: Pushrod For ce Charts ........................................ .... ................ 4 17 Bibliography ..... ..... .... ........ .............. .... ................. ........ ..... ..... ....................... 427 About the Authors ......... .. ...... ..................................... ... ................................ 431 lndex .. .... ..... ................. .... ............. ..... .... ... ..... .................. ............................... 435

Acknowledgments

This text is dedicated to our wives, Mary Lou Varner and Am-Mialye Sutphen, and our families who have supported us during the last several years, through long days and nights, while we gather information, write and re-write the text, and gather our thoughts, concepts, and graphics for this manual. Additionally, we wish to thank our many friends , past co-workers at the Pennsylvania Institute for Law Enforcement Education, Pennsylvania Department of Transportation, manufacturers, transportation companies, and peers who assisted in many ways in providing materials, knowledge, and experience. We wish to provide a special thank you to Ronald Hauser for his professional knowledge and other contributions, and to Larry Guise and the Michelin Tire Corporation for their assistance and expertise in providing us materials to make this manual possible. In addition, we would like to thank Dennis McGee for his contributions to several chapters in this textbook. Dennis' knowledge, experience, and expertise were of immense value in updating this manual. It would not be proper to om it our gratitude to Jeffrey (Butch) Kostan, John Tippery of Sheetz/CU Transport, Inc. and Lynn Manges of Interstate Emergency Service for allowing us access to their vehicles for photographic documentation. - Rick W. Varner and Roy F. Sutphen, Sr. I would like to extend a special thank you to my son. Sean M. Varner, for his assistance in researching materials, acquiring photographs, proofreading materials, and providing me with writing and research assistance, concepts, and other aspects of this manual. This was an invaluable service to me. Sean is currently attending Goucher College in Towson, Maryland. He is planning on obtaining his degrees in English and History. I hope his experience in assisting with this manual wi ll be found to have been a great value in his education. It certainly is a learning experience for me.

v

vi

Commercial Vehicle Accident Reconstru ction and Investigation

Just prior to the first edition (2003) of this textbook, my father Loris W. Varner passed away and I gave him an acknowledgement in that edition. l would like to acknowledge him in this second edition. I miss him every day. May God bless hLm. Twould also like to recognize my mother, who is still living. - Rick W. Varner

Chapter 1

Introduction

History The beginning of the motor vehicle age goes back before Henry Ford and Company. In fact, we can trace it back to the Fre nch when a military engineer, Nicholas Cugnot, built a three-wheeled, steam-driven vehicle that was reportedly used to pull artillery parts. The first automotive accident was when it ran into the wall. Shortly thereafter, other steam-driven veh icles were produced. Some of these vehicles were improved ~node ls, wh ile others would not work at all. Automobiles, trucks and other vehicles that were gasoline driven came in existence around 1886. The credit for these vehicles must go to Karl Benz and Gottlieb Daimler who worked independently.

Figure 1. 1 8 Model Mack.

2

Commercial Vehicle Accident Reconstruction and Investigation

In the United States, the automobile industry began to tlourish by I 908. Henry Ford was manufacturing the Model T, and General Motors was founded. In Europe, other automobile manufacturers were well known, such as Renau lt, Benz, Peugeot and Daim le r. Around the year of 1909, over 600 American cars had been recognized. Today, there are more trucks, buses and cars on the road than ever. In this text we will primarily concentrate on trucks and buses. These vehicles are becorning longer, wider, higher and heavier, while cars, on the other hand, become smaller. As the number of vehicles trying to share the highway is rising, the number of collisions between these two types of vehicles become more of a public concern.

Media Although the news media have labeled the commercial vehicle as "killer trucks," our predominant legislatures have increased the speed limits across the country. Many states now allow trucks to travel 65 mph, and some states are even looking at allowing vehicles to travel above 65 mph. It goes without saying that vehicles can travel the highways above 55 mph and, if there is not an emergency, both types of vehicles can use the highways without incident. If an emergency circumstance becomes evident and emergency brake application is warranted, now the problem begins to unfold. Do you want one of these large trucks behind you at this time? Well, we shall allow you to ren.d er this decision. Statistically, it has been determined that for every mile of highway, there are over forty-five vehicles trying to share the highway. And over this same mile of highway, each vehicle will commit a traffic offense three times. or a total of 135 traffic violations will occur over this mile of highway. The increase in bus and truck travel will continue to grow in this country over the next couple of years and is expected to continue to increase. Simply put, there will be more drivers operating more vehicles. This is one of the reasons the public pushed to have the commercial vehicle drivers licensed or qualified to drive the vehicles that they currently drive. There are over J60 million licensed drivers in the United States. This number is inconceivable for most of us to consider when we are operating our own vehicles. Because of this high number of drivers, the other users of the highway deserve some type of assurance that the drivers of these big trucks are qualified to drive the vehicle they are operating. The definition of the word truck, cou ld be anything from a 2 ,000-pound pickup to a 250,000-pound mine hauler. For the purpose of this text, we will define the term truck to be a commercial vehicle as defined by legislation.

1. Introduction

3

Since this text is for accident investigations and accident reconstructions, we will limit the commercial vehicle to the above mentioned definition. In regards to the accident situation~ it is made worst when the news media broadcast on the local or network new programs that the accident involved a commercial vehicle. Commercial drivers are involved in more than 440,000 crashes annually. When an accident involves a commercial vehicle, the risk is to the people outside of the truck. The occupants of passenger vehicles, pedestrians and even people in stores and residences are at the greater risk than the driver of the commercial vehicle. This is especially true if the CY was transporting a hazardous material. If a bus is involved in the accident, then the occupants inside the bus are also at a high risk. The worst situation would be if a heavy truck and a bus would be involved in the same collision. The operation of trucks and buses places a distinctive requirement on the drivers of these vehicles. Longer stopping distances, less maneuverability, cargo shifts, brake fade and so on. These are only a few of the problems that the drivers of these vehicles face. Throughout this text and in greater detail we will discuss many other difficulties that face the drivers of these large vehicles. The skills of the driver will need to be addressed since they are more complex than those of the automobile driver. Cars can maneuver quickly, while a truck's response is slow. This causes the commercial vehicle driver to make up for the size of his vehicle. This will command greater distances for turning, passing, stopping and accelerating. What does this mean to us? The driver must have the sufficient time and distance available to plan ahead. If the driver is running at 100 percent of his or her ability, neither the time nor the distance will be available to avoid the collision. Congress passed the Commercial Vehicle Safety Act of 1986 in an attempt to address these issues. This act directed the Secretary of Transportation to issue minimum testing standards to guarantee that the drivers of the commercial vehicles were qualified to drive these vehicles. These standards include both written and driving tests. One final thought before we continue into the subject matter in greater detaiL There is an abundant number of people entering into the field of traffic accident reconstruction. T hey may be forensic engineers, law enforcement officers, either active or retired, or people from other forms of related industry. Many of these people merely have a basic level of training and attempt to become a specialist in certain areas. _The field of motor vehicle accident reconstruction demands more than a basic knowledge. It does not matter if the collision is a single vehicle, a motorcycle, a pedestrian or the commercial vehicle. Each of these types of accidents is a speciality and the person hired by the attorney or insurance carrier to represent the client should be aware of this fact.

4

Com mercia l Veh icle Accident Reconstruction and Investigation

Before you as the investigator or reconstructionist accept a case, please be certain that it is within your ability to do the job you are expected to do. Do not be afraid to contact other people to assist you. The medical community does it al l the time.

Truck Accident Reconstruction I n the area of accident recon struction the most misunderstood is the commercial vehicle accident. I have conducted many analyses of police reports and reports from other experts such as engineers or an accident reconstructionists and it is not uncommon to find errors dealing w ith braking efficiency, basic dynamics, engine speed, rollovers and so on. In most cases these reports deal with the articulated vehicle commonly referred to as a scmj or truck/tractor. Most of these eiTors can be explained because the investigator or reconstruction is! does not have specialized train ing in the area of commercial vehicle accidents and relies on his or her basic training as it related to the passenger vehicle. On other occasions, the investigator fai Is to obtain sufficient or proper data from the accident site or the crash vehicles. It is not uncommon for the investigator to rely on average factors, especially in a rollover type of collision. In many of these cases the investigator does not even attempt to determine the loading condition of the vehicle. In the area of motor vehicle accident investigation, th is manual will identify the proper methods, techniques and data that must be collected from the vehicle, the accident site and, in some cases, the manufacturer and the trucking company to assure a proper analysis of the collision.

What Is a Truck? T he term truck can refer to anything from a 2,000-pound pickup to the largest piece of construction or mine equipment that weighs more than 255,000 pounds. For our discussion in this manual we w ill be referring to the commercial vehicles and not the passenger type of vehicle such as your 4 x 4 pickup trucks or your two-wheel-drive pickup trucks, unless they are towing a trailer. When a l ight truck pu lls a trailer, it becomes an articulated vehicle, and can be a problem when the driver only drives the truck and trailer once or twice a year. At first when they pull out from home they are very careful; but give them a few miles, and they forget that there is a trailer on the rear that does not allow the vehicle to stop as quickly as before, and also places restrictions on cornering and so forth. The one time a year truck and trail.er driver is also apt to forget to adjust his electric brake controller properly, setting into motion a problem that can certainly cause, if not become, an accident, because of brake instability.

1. Introduction

5

Figure 1.2 Typical light truck.

Figure 1.3 Typical m edium-weight truck.

Light trucks (single unit, less than 10,000 pounds) The light trucks are manufactured by companies such as Chevrolet, GMC, Jeep, D odge and Ford. These are two-axle vehicles, w ith hydraulic brakes and are not covered under the COL legislation. These vehicles are much like an automobile in that they have independent front suspension and the drive trains are made up in part by the sam e components as that of the automobile, such as engines, tires, wheels and so on.

Medium-weight trucks The next level of truck is the truck that can carry a moderate weight l oad. Generally speaking these trucks will also have a hydraulic braking system , be equipped

6

Commerc ial Veh icle Accident Reconstruction and Investigation

with the leaf springs and in most cases have drum brakes on a ll w heels. The most common type of rear axle on this type of vehicle wi ll be the dual axle. These vehicles include most school buses and type-A motor homes.

Figure 1.4 Typical heavy-weight truck.

Heavy-weight trucks The vehicle we will be discussing is the heavy articulated vehicle. With this vehicle the tractor o r the power unit will have two or more axles. The heavy truck will be equipped with an air braking system and essentiall.y be powered by a diesel engi ne. T he weight range on these vehicles will begin at 20,000 pounds and will exceed 80,000. These trucks will vary in length from approximately 55 feet to over 75 feet. This depends on the jurisdiction, highway and in some cases permits that are available. The width on the vehicle may be between 96-102, inches and the height is normally not permitted to exceed 13 feet 6 inches. Naturally, with a special penn.it, any of these specifications can be exceeded.

Weight Ratings The Administrator of the National Highway Safety Adm inistration issued an announcement which broadened the definitions used in the Federal Motor Safety Standard to the regu lations contained in Chapter V of Title 49 of the Code of Federal Regulations (CFR). 49 CFR Section 57l.3(b) incl udes the definitions of weight ratings under the Federal Motor Vehicle Safety Standards. Be careful when reviewing these regulations, because several of the regulations, other than those identified as standards, contain their own definitions of terms pecu liar to the regulation and otherwise incorporating by reference the definitions of Part 571 .

1. Introduction

7

To avoid total confusion on this matter, the Administration determined that the definitions used in Part 571 shou ld apply to all the regulations under Chapter V; however, part of 568 should be amended by deleting the definitions of "gross axle weight rating" and "gross vehicle weight rating." The more si.gnificant definitions applying to weight ratings may now be found in Part 57 I , Federal Motor Vehicle Safety Standards. They are: •

•

cu r b weigh t. The weight of a vehicle with standard equipment, maximum capacity of engine fuel, oil , and coolant, and, if so equipped, air conditioning and additional weight optional engine. gross axle weigh t rating (GAWR). The value specified by the vehicle manufacturer as the load-carrying capacity of a single axle system, as measured at the tire-ground interfaces. gross combination weight r ating (GCWR). The value specified by the manufacturer as the loaded weight of a combination vehicle. gr oss vehicle weigh t r a ting (GVWR). The value specified by the manufacturer as the loaded weight of a single vehicle. unloaded vehicle weigh t. The weight of a vehicle with maximum capacity of all fluids necessary for operation of the vehicle, but without its

cargo or passengers.

Distribution of the Vehicle's Weight When the design of the vehicle is considered, from the selection of the chassis to the final assembly of the vehicle, the critical factor is the amount of weight that will be expected to be carried on each of the axles. The gross weight of the vehicle is an influential part of the overall design. The weight ratings are vital in determining braking requireme111ts and total stopping distances as required by the Motor Vehicle Safety Standards; however other areas of importance are affected by these ratings in addition to the braking and stopping distance requirements. T hese considerations range from economic considerations to the safety requirements and considerations. The vehicle must be designed to meet various state and federal guidelines. Most importantly, a vehicle that is designed properly will assist in reducing highway accidents. A vehicle that is improperly designed may contribute to the collision. Loads that arc overweight or improperly loaded will affect safety and can cause mechanical or component problems. Special attention during the vehicle inspection should be given to the tires. Rapid tire wear may indicate the weight on the tire exceeded the load rating for that tire. If the vehicle in question is a cab-over, pay special attention to the steering tires because it is easy to exceed the rated capacity.

8

Commerc ial Vehicle Accident Reconstruction and Investigation

A wandering ride or rough ride will indicate the load is either directly over the rear axle or slightly behind the rear axle. This type of ride is because of the lack of sufficient weight on the front axle, and it creates a very rough ride. An overloaded front axle will affect the steering mechanism. The result wi ll be that it is difficu lt to steer. This will also create a possibility of premature failure of components which may result in any of the following or a combination of any of the fol lowing:

• •

The kingpin or tie rod has abnormal wear. The wheel bearings may fail. The front axle may show signs of fatigue, or it may be bent, or both. There is an overload on the front springs.

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414 Commerc ial Veh icle Accident Reconstruction and Investigation

Wr

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Acceleration factor Another formula that will be possibly needed during commercial vehicle reconstructions is the formu la to determine the acceleration rate of a truck involved in an accident at an intersection. d

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a= 32.2/

(Equation 29.8)

where f = acceleration/deceleration factor, d =distance traveled, and t =time to travel the distance.

Acceleration rate If the acceleration factor is known,

where a= acceleration rate in feet/second 2•

f = acceleration factor, and 32.2 = gravity/second2 •

29. Other Speed Formulas

415

Time Shou ld the investigato r need to know how much time it too k the truck to accelerate from a stop or decelerate to a stop when distance and acceleration/deceleration factor are known. (Equation 29.9) where t = time in seconds, d =distance traveled, f = acceleration/deceleration facto r, and 0.25 = constant (actually an algebraic manipulation of the equation d = 16.1 ft 2).

Appendix A

Pushrod Force Charts

41 7

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Bibliography

Air Brake Book, Sixth Edition, Commercial Carrier Journal, Radnor, 1998. Air Brake Handbook-Components-Maintenance-Troubleshooting. Bendix Heavy Vehicle Systems Group, Elyria, Ohio, 1983. Air Brake Handbook. Bendix Heavy Vehicle Systems, Elyria, Ohio, 2009. Air Brake Manual, Insurance Corporation of British Columbia, 1998. Air Brake Service Manual. NAPA United, 1988. Air Brake Systems and Components. Bendix Commercial Vehicle Systems, 901 Cleveland Street, Eylria, OH. Barzelay, Martin E. and Lacy, George W., Scientific Automobile Accident Reconstruction, Matthew Bender and Company, Inc.. 1999. Champion Trailers: Technical Information Articles. www.championtrailers.com. Daily, John, Fundamentals of Traffic Acciclenl Recons1ruction. Institute of Police Technology and Management University of North Aorida, Jacksonville. 1988.

Factbook of !he Mechanical Properties of the Components for Single-Unit and Articulated Heavy Trucks, Report Number DOT HS 807 125, U.S. Department of Transportation. Washington. 1986. Federal Motor Carrier Safety Regulmions 49 CFR. U.S. Department of Transportation, Washington. 2001. Fitch, James William, Motor Truck Engineering Handbook , Fourth Edition, Society of Automotive Engineers International. Warrendale. 1994. Fricke, Lynn B.. Traffic Accident Reconstruction, Volume 2 of the Traffic Accident Investigation Manual. Northwestern University Traffic Institute. Evanston. 1990.

427

428 Commercial Vehicl e Acc ident Reconstruction and Investigation Fundamentals-of Brakes-of Compressed Air- of Compressed Air Brakes, Bendix Heavy Vehicle Systems Gro up, Elyria, Ohio, 1987. Gun.ite Heavy-Dury Brake Drums Maintenance and Installation Manual, Gunite Corporation, Rockford, 1997. Heavy Vehicle Airbrake Petjormance PB92-917003 NTSB!SS-92/01, National Transportation Safety Board , Washington 1992. Heusser, Ronald B., Heavy Truck Deceleration Rates as a Function of Brake Adjustment, SAE 910126, Society of Automotive Engi neers International, Warrendale, 1991. Heusser, Ronald B. EA5. Air Brake Efficiency-Calculation Methodology. 2010. Hunter, John E., Cartier, ScottS., Temple, David. J. , a nd Mason, Robert C., Brake Fluid Vaporization as a Contributing Factor in Motor Vehicle Collisions. SAE 980371, Society of Automotive Engineers International, Warrendale, 1998. Lofgren, M. J., Handbook for the Accident Reconstructionist, 3rd revised ed., Insti tute of Police Technology and Management University of North Florida, Jacksonville, 1987. Mariolani, Jose Ricardo L., Schmutzler, Luis 0. F., Arruda, Antonio Celso F. a nd Occhipinti , Sidney, Impact Project: Searching for Solution to the Underride Problem, SAE 982755, Society of Automotive Engineers International, Warrendale, 1998.

Meritor WABCO: Braking Systems and Controls and Safety Systems for Commercial Ve hicles, Air Compressors, Air Dryers, Air Brake Control Valves and Air Disc Brakes, Pneumatic Anti-Lock Braking (ABS), Automatic Traction Control (ATC), SmartTrac, Stabil ity Control Systems, ABS Systems ECAS for Trucks, Tractors and Buses, Stability Support (RSS). Troy, Michigan, 2006/2007. Meritor Wedge Brakes Maintenance Manual No. 4R, Meritor Heavy Vehicle Systems, Troy, 1995. Motor Truck Repair Manual, 3 1s t ed., Motor, New York, 1978. Napa United Air Brake Service Manual, Mitchell International , Inc. , San Diego, 1988. NTSB Safety Study Heavy Vehicle Airbrake Performance. PB92-917003 NTSB/SS92/01.

Bibliography

429

Radial Tire Conditions Analysis Guide (A Comprehensive Review of Tread Wear and Tire Conditions) , The Maintenance Council, Alexandria, 1994. Radlinski, Richard W. and Williams, Sydney F. NHTSA Heavy Duty Brake Research

program Report No. 1 -Stopping Capability of Air Braked Vehicles Volume / Technical Report. Report No. DOT HS 806 738, April 1985. Recommended Maintenance Practices Manual-Rim and Wheel Selection and Maintemmce, The Maintenance Council, Alexandria, 1994. Recommended Maintenance Practices Manual-User's Guide to Wheels and Rims, The Maintenance Council, Alexandria, I 994. Technical Information Articles, from Internet site at www.championtrailers.com. Champion Trailer Parts Supply, Slidell , 1996.

Truck Systems Design Handbook PT-41 , Society of Automotive Engineers International_ Warrendale, 1992. U.S. Highway Safety Administration, DOT HS 809 883.

Wheel & Rim Manual. National Wheel & Rim Association (Jackson\'ille. Florida). While, Andrew J. Brake Dynamics: An introduction to vehicle brake testing at the inspection station level. Motor Vehicle Research of New Hampshire (Lee, New Hampshire), 1963.

About the Authors

Rick W. Varner currently serves as a Magisterial District Judge in the 47th Judicial District of the Commonwealth of Pennsylvania. Rick began his service as a Magisterial District Judge in 2006, after retiring as the Director of the Institute for Law Enforcement Education (ILEE). He served as the Director ofTIPS/lLEE from 1983- 2005. Rick began his career as a police officer just twelve days after his 18th birthday; he was the youngest person to be sworn in as a police officer in his county. He was active in that position for over 32 years. In 1982, he took a position with the Pennsylvania Department of Education 's Traffic Institute for Po lice Services and continued to maintain his position as a police officer. In 2006, he retired as a police officer to serve on the bench as a Magisterial District Judge. As Director of the Traffic Institute for Police Services (TIPS), he received his training in many specialized areas. Rick is certified on more than 78 chemical breath test instruments, not only to conduct testing but to perform maintenance and instructor certifications. He has instructed students. both nationally and internationally, in numerous specialized areas, and is probably best known for his work, training, and research in the area of chemical breath testing, alcohol-related training and traffic accident reconstruction. In 1983, while still Director at TIPS, Rick accepted the position of Accident Reconstruction Expert at the Pennsylvania Department of Transportation (PADOT). This position was needed to assist a local Pennsylvania police agency, as there were no police accident reconstructionists in the state at that time. PAOOT requested T IPS take the lead in obtaining and providing the training throughout the state. This training continues today, funded by PADOT and delivered by fLEE. Rick considers himself fortunate for the opportunities that were provided to him through his position with the state. T hat ho lds true today. He still makes himself available when PAOOT or other state agencies call for assistance or expertise on various subjects.

431

432 Commercial Vehicle Accident Reconstruction and Investigation In 1986, he began to train state and local law enforcement officers throughout the Commonwealth of Pennsylvania in collision analys is and reconstruction. It was during this time that he served as an instructor in this field whjle still maintained the position as the Director of the program. He was able to bring additional staff on board to assist with the collision-related training. He has trained personnel from the National Transportation Safety Board 's Heavy Truck Crash Unit as well as National Highway Traffic Safety Administration's law enforcement officers, United States and international military and Jaw enforcement personnel, e ngineers, and medical personnel. He has served as an expert witness in various state and federal courts. He always felt he learned as much from the students as the students learned from him. In 2002, as Executive Director of the program, Rick changed the name of the Traffic Institute for Police Services to the Institute fo r Law Enforcement Education. The training he developed while at the Traffic Institute for Police Services was recognjzed by the appellant courts, which determined fo r the allowance of the officers who attended the training at the reconstruction level or above to qualify as expert witnesses in the field of accident reconstruction. He has actively participated in numerous test studies, including but not limited to commercial vehicle rollovers, commercial vehicle brake testing, Michelin 's tire failure program, automobile crash testing, motorcycles, pedestrians, school buses, commercial vehicles, bicycles, nighttime collisions, ambient and artificial lighting systems, vehicle and material reflectivity, and more. He has also participated in test studies of headlamp examinations, and coefficient of frictions on various surfaces. Rick has attended numerous air brake training courses including Bendix Brake Systems, NAPA and Meritor. He has also trained in heavy duty trucks and electronic control modules at Mack Trucks, Inc. He has attended training by the NTSB , USDOT, and AOBRD in heavy truck accidents relating to braking efficiency and rollovers. He has instructed privately and for the Institute for Law Enforcement Education for more than 30 years, deve loping and teaching in the commercial vehicle and other related accident reconstruction programs. Rick has also been qualified as an expert witness in various courts including the federa l level as an accident reconstructionist in various subject matters, as well as in the area of chemical breath testing (operation, maintenance, instructional), nighttime visibility, alcohol and drug impairment. Rick currently resides in Seesetown, Pennsylvania, with his wife Mary Lou and his son Sean who attends college at Goucher College, in Towson, Maryland.

About the Authors

433

He is still active in his accident reconstructio n consulting business and training programs, Spectrum Consulting Gro up. Rick is currently a member of the Society of Automotive Engineers, National Association of Accident Reconstructio nist, and Pennsylvania Special Courts Association.

Roy F. Sutphen, Sr., Vice-President, Spectrum C onsultant G ro up, who resides in New Paris, PA. retired after twenty-five years with the Pennsylvania State Police. where he was assig ned to the Patrol Division. While with the Pennsylvania State Po lice he was trained as an accide nt reconstructionist and a motor carrier inspector, assigned to Troop "T" which patrolled the Pennsylvania Turnpike. In this capacity he investigated all major accidents that occurred within a 100-milc area of his station. Mr. Sutphen has attended air brake training with Bendix Brake Systems, Napa and Meritor, along with training at Mack Trucks, Inc. on heavydut y trucks. He has also atte nded training by the NTSB and US DOT in heavy truck accidents, re lating to braking efficiency and ro llovers. Since retiring fro m the Pe nnsylvania State Police in 1992, Mr. Sutphen has joined Spectrum Consultant Group, which is an accident reconst ructio n business enterprise. He has been on the adjunct staff of the Institute for Law Enforcement Education for thirteen years, and c urrently develops their commerc ial veh icle programs. Mr. Sutphen i a member of the National Associatio n of Professio nal Accident Reconstructionists, (NAPARS) and the Soc iety of Auto motive Engineers, (SAE).

Index

articulated vehicle, 4, 6, 241, 345, 350-

A ABS brakes, 107,398 acceleration rate, 4 14 adverse drivi ng conditions, 28, 38, 84,

87 aggressive dri ver, I ll, 327 air brakes restrictions, 58 air compressor, 187-189. 211. 213.224.

244.299 air dryer. 187-189.257 air over hydraulic brakes. 211 air pressure. see also tire pressure gauges, 194,238 air ride suspension, 259 air suspens io n, 156 air valves, 252. 255, 257, 30 I alcohol, II, 19. 2 1, 49. 52-53. 55. 59, 84,

187' 189. 279, 311. 319-320. 324 alcohol injector, 187, 189 alignment, I 00, I 06. JJ I, I 43- 145. 148,

226 American Trucking Association, 10 anchor pins, 168-169, 225 an ti-compounding system, 187, 202 q uick-release valve. sec qu ick-release valve applicatio n pressure, 197, 224. 231-232.

418-425 argo. 370 arm. 12. 141 - 143. 145. 148. 150, 226.

245.302.305. 355 armature. 180 articulated. 4, 6, 241, 270. 345. 350-351.

363

351 A-trai n, 136-137 auto transporters, 268 auto matic onboard recording device, 38,

44-45, 369, 397 axle loads, 113-114, 264 axle weights, 7. 101.245-250, 267

B backup lamp. 69 ball, 12.138-139. 141. 3 17 battery box. 72 bias-belted tires, 98 bias-ply tires, 98 bill of lading, 15, 303, 323 bli nd spot, 3 11 , 321 bluing, 170-171, 177 brake adjustment. 171. 195, 229, 232, 254 indicators, 195 brake application, 2, 146, 153, 157, 200,

204, 208, 224, 227, 253-254, 256, 301,347,377,385,395,399 brake cam, 195 brake chamber, I 52, 162, 19 1, 195- 196, 200, 202, 2 17. 219, 223-225, 227, 229-23 1,234,24 1,244,252,257 size, 219, 229-23 1, 234, 252 brake controller, 4, 183 brake drums, 94, 163-165, 168-170, 175, 179-181, 195, 202. 211. 217-219. 223. 225, 228. 233. 237, 251-253. 256-257 radius. 237 temperature, 233

435

436 Commercial Vehicle Accident Reconstruction and Investigation brake fade, 3, 8, 227, 256 brake fluid vaporization, 176, 302 brake force, 162, J65, J67, 170, 173-174,

218,220,233,240-242,253,412 brake instabil ity, 4 brake lining, 164, 168-169, 195, 218,

226,235-237,252,254,256,292 coefficient of friction , 235, 254 brakeshoe, 161-162, 164,168-169,175,

179-180, 182, 195, 202, 2 11 , 217219, 223, 225-228, 251, 256, 289, 297,300,303 brake temperature, 233 brake timing, 165, 253 brakevalve, 161 , 198 braking efficiency, 4, 98-99, 197, 220, 222, 229, 231, 240-242, 292-293, 4 11 braking system, 5-6, 8, 58, I 02, 14 1, 167, 176, 182, 185, 215, 226, 253, 260, 289, 292-293 breakaway switch, 180-181,303 breakaway system, 180- 181 broken studs, 91 , 93 S-train, 136-1 37,350 Budd wheel, 89 bumper, 136, 139, 276-279, 315, 356 hitch, 136, 139 buses, 2-3, 6. 13, 22, 39-40, 42. 47, 62,

69-70, 96,24 1 butane, 118

c cabs, 66-67, 11 9-120, 122, 14 J, 205,

207, 274, 301, 304-305, 314-316, 3 18,321,337,348, 380,387,398 cab-over, 7 cage the brakes, 229 caging bolts, 232 caliper pistons, 164 cam shafts, 16 I , 235 camber, 1 II, 143-144, 147 cameras, 321, 330, 334-337, 381 -382 cammed over, 232 cannabis, 324, 326

carbon monoxide, 119 cargo, 3, 7-8, 17. 21, 27, 59, 62, 101 ,

112- 114, 152, 176, 259-260, 269, 283-284,298 cars, 2-3, 146, 164, 227, 278, 381, 397, 400 center of mass, 245-246, 260, 266, 268, 27 1' 304, 349-350, 353-360, 362363. 365-366.411-4 12 displacement, 362, 365-366 for the vehicle, 245, 266, 271, 353, 356, 359-360, 366 formula, 356 of the load, 245, 27 L 353-354, 358, 360,366 chains, 139, 185, 284-285, 347 chocks, 163, 30 I , 309 civi l twilight, 329-330 clevis pin, 235 Code of Federal Reg ulations (CFR), 6, 9, 18,25,47,49,57,59,62,65, 74, 115, 185, 193,241,273, 278,283284, 320,323-324,370,397,399 coefficient of friction, 98, 168-169, 2 16, 220, 235, 240-241' 252, 254, 291292,360 commercial driver's licenses (CDL), 5, I 0, 29-30, 47-52, 54-58, 60, 63 commercial motor veh icle (CMV), 21 22, 26-3 1, 37-39, 47-53, 55-59, 95-96,1 15,283-284,287,370,372373,393-398,405 commercial vehicle drivers, 2-3, 324 Commercial Vehicle Safety Act of 1986, 3 commercial zone, 17 common carrier, J5-17 complex reaction, 241 component failure, 8 compound loads, 262-263 compressed air, 61, 119, I 59-162, 188189, 191,207,213-214 compressors, 161 - 162, 187-189, 191 , 193,211,213,224.244, 299,30 1 concentrated loads, 260-26 1

437

In dex consecutive hours off duty, 26, 28-34, 37-38, 40-4 1 contai ner chassis trai lers, 268-269 contract carrier, 16, 48 contrast sensitivity. 321 . 332 coupling devices. II, 21, 23, 131 cracked drums. 170-171 C-train, 136-137, 350 curb weights, 7

D dash control valve, 20 1-202 datum, 245-246. 248, 355-356 Dayton wheel, 89 debris, 178,287.297-298,302 depressants, 324-325 depth perception. 279. 319 designs, 97, 166. 260 diaphragms, 162, 195, 218, 223-224, 300 digital cameras, 336 Digitax black box and tachograph, 371 disc brakes, 164, 173-174,223,227-228 disqualification or drivers, see driver disqualification disqualifying offenses. 53 distributed load, 261-263 dolly converter, 69, 135-1 36, 272, 342 double trailers. 135-136, 256, 27 1-272, 341-342,349 drag link. 141-143.305 draw bar eye, 135 dri ve axle, 90. 106-107, Ill , 115, 132, 195,23 1,248-250,347.394 driveline brake. 215-216 driver disqualification, 19, 52-53 driver inspection , 23-24 driver vehicle inspection report, 23-24 driver's home terminal. 45 driver's license suspension, 51, 55 driver's record of duty status, 23-25, 42, 397.399,404 driver's skill, 317, 326 driving time, 25-29. 33, 37-42. 371

driving while under the influence of alcohol, 49. 52-53, 320 drop vans, 266 drugs, 10, 21,279.3 17-320,324 drum brakes. 6, 163-164. 173-174, 227 dual axles, 6, 112 dual wheels. 13, 94, 98, 100-10 I, I06, 108, 110- 111 , 135. 295, 304, 340. 360,365 dump trailers. 266-267 dynamics, 4, 295, 314, 345, 350-35 I

E Eaton VORAD collision warning system, 383 eccentric loads, 263 economic regulations, 9, 17 electric brake , 4. 179-183, 186. 303 electronic control module, 371, 373-374, 398 electronic engine controls, 374 emergency breakaway system. 180 endorsement, 50, 54-56. 58, 60-62 engine retarders. 166, 213-2 14, 383 engine speed, 4, 370, 373-374, 378, 382383,409 e caping loads, 283 exempt carriers. 15-17 exemptions, 19-20, 22, 26, 38 exhaust brakes. 214-215 exhaust manifold, 119 exhaust system, II, 11 5, 119, 129

F 14-hour on-duty time rule. 32. 34. 38 49 CFR, 6. 9, 25. 47, 49. 57, 59. 62. 65, 74, 115 , 185, 193, 24 1, 273, 278, 283-284, 320, 323-324, 370. 397, 399 false log, I I , 43 fatigued operator, 20-2 1 Federal Highway Administration (FHA), 9,20.25.45 federal motor carrier safety regulations. 9, 17.283,399

438 Commercial Vehicle Accident Reconstruction and Investigation federal motor safety standard, 6 fiber rope, 285 fifth wheels, II , 13 1- 136, 139, 240, 249, 272,308-3 10. 349 fire extinguishers. 21 . 59, 122 Rat spot, I08 flatbed trailers. 267. 284, 358 fluid depth, 407 fl uids, 7, 162, 175- 178, 188-189. 295296,302-303,3 15,407 foot valve, 168, 195-200, 218, 223-224, 232,241,337,349 foundation brakes, 115, 168-169, 179, 195, 200,202,30 1 frame members, 26 1. 264 frame rail, 3 15 free backing brakes. 185 front axle. 8. 12. 11 6. 143, 166-167, 193. 195, 197,204.252,347,4 11-412 limiting valves, 167, 197, 252 front clearance lamps, 66 front identification lamps, 66 front suspensions, 5. 14 1, 150. 276 front turn signals, 65-66. 69 front wheel limiting system. 195 fuel crossover lines, 11 6 fuel economizer. 119 fuel lines, II , 115- 11 7, 119, 126-129, 316 fuel pump, 115, 118 fuel tank, 70, 73 , 11 5- 117, 12 1- 122 filler cap. 115

grease-soaked lining, 237 grommet, 70 gross axle weight rating, 7 gross combination weight rating, 7, 49, 57 gross vehicle weight rating, 7, 25. 49 gross weight. 7 Group A combination vehicle, 57 Group 8 heavy straight veh icle, 57 Group C small vehicle, 57

G

I

gap skids, 290. 293 gladhands, 205-207, 23 1, 253, 301 glaucoma, 333 gouges,295,297-298,348 governor, 187, 189, 19 1- 192, 224, 301, 374 granular cargo. 298 grease, 70, 132. 135. 178. 225-226. 228, 235,252.256,30 1-302,309

H hallucinogens. 324-325 hazardous materials, 3, I 0, 13, 22. 26. 48-49, 53-58, 60, 62-63 endorsement, 54-56, 58, 62 headlamps. 10, 12, 65, 67, 69.76-77,80. 83-84. 276. 328-330,332-334 hearing aid, 10, 20, 22 heat checking, 169-1 7 1 heavytruck,3,6,77, 165, 167,213,229, 24 1. 309,31 1. 383 heavy-weight trucks, 6 high center-of-mass loads, 263-264 high hookup, 135 horn. 21.23 hours of service, 18, 25, 39, 45. 370 human factors, 317 hydraulic braking system, 5 hydraulic flu id, 175- 176 hydraulic surge brake systems, 185 hydroplaning. 174,407-409

identification lamps, 66-67, 69,279 implied consent to alcohol testing, 55 inhalants, 324, 326 interstate commerce, 9, 15- 18. 185, 397 Interstate Commerce Commission, 9. 15-17 intrastate commerce, 9, 18 inversion valve, 204

Index

J jacknife, 8, I I , 183, 2 I 4, 24 I, 253-255, 293, 337, 345-348 jake brake, 213,2 16,304

K "killer trucks", 2 kingpin, 8, II, 13 1-1 32, 134- 135, 142143,246-249. 341 knuckle, 142-143

L lamps, 12, 65-67. 69-70, 73, 75-80, 8285.181.279.312.330,339 large trucks, 2, 165, 292 leaf springs, 5-6, 153 license plate lamp, 69 lights, 12, 18, 21 , 23, 48, 59,65-66,68,7 1, 73, 78,175,200,275-276,279. 288. 326-329,332,334.336,339,382 liquified petroleum gas (LPG). 116-118 livestock trailers, 269-270 load ranges. 96 load securement, 2 1, 283 loads. 7, 12, 40, 43. 69. 110, 114, 154, 211' 260-265, 271' 283, 304, 322, 354, 358-359. 396 low-pressure switch, 187. 189 lowboy trailers, 267-268

M magnets, 180-182, 303 maintenance, 22-23,59,95-96, 100-101. 111-11 3, 11 8, 123- 124, 164-165, 193, 214, 225. 227, 235. 254. 257. 297,370,379,394,400,404,406 manifold, 117,119 Mannesman VDO. 370 manual drain valve, 191 , I 93, 197 martensite. 171, 173, 177. 301-302 master cylinder, 175-178, 185,302-303 mechanical. 7-8,38, 115. 161. 168. 179, 185, 201, 214, 220. 229. 241 . 337, 363,370,399

439 mechanical advantage, 220 mechanical lag time, 168.229,241 ,337 medical card. 321, 323, 404 medical examiner's certificate, 20 medjum-weight truck, 5 mirrors, 21, 23, 59, 73, 252, 304, 311, 3 15, 320-32 1 moistureejector. 187, 189. 19 1 motor carrier, 9, 15-18, 20-30, 39-40. 45, 50.52.283-284,320.370,396-397. 399,404 multi-piece ri m, 89

N National Driver Register, 56 National Transportation Safety Board (NTSB), 220. 251, 358, 372, 399 night myo pia, 333 nighttime photography. 334, 336 nighttjme visibility, 74, 328 no zone. 320-322

0 Office of Motor Carrier Safety. 9 offset skidmarks. 293-294 off-track,61. 139. 271,339-341 onboard computers. 45. 369, 37 1. 403404 on-duty not driving. 27-28 one-way check valve. 193 out-of- ervice, 9- 11. 19. 35, 50.52-53 overinflated, 99- 100 overloaded vehicle, 8 overloading. 91. I00, I02 overweight, 7

p parking brake, 21-23, 176-177. 199. 202. 204, 208, 2 11 ' 30 1-302 passengers. 3-4. 7. 15-17, 25-29, 37-41. 49, 54,57-58,61-62,76, 83. 98-99, 119, 122, 125. 129. 176, 227, 240. 274, 279. 292. 311. 314-315. 397. 400,409 PC P. 324-325

440 Commercial Vehicle Accident Reconstruction and Investigation perception. 59. 73. 241, 279. 319. 326, 337 physical evidence, 9 1, 117, 287-288. 31 1, 369-370, 372, 380 pintle hooks, I I, 135-136, 272, 342, 349-350 pitman arm, 12, 141, 143,305 platform trailers, 267, 362 pop-offvalve. 187. 189-190 power unit, 6, 23. 60. I 15 pre-trip inspection, 2 I, 60 primary reservoir, 197-198 primary tank, I97-198 private carriers, I7, 96 propane gasses, I I 8 Public Utilities Commission, 9 push rod, I65, 185, 195, 200. 202, 220, 223-225,229,231-234.300.417 force, 195, 220, 233-234, 4 I 7 stroke, 165, 195,23 1-234. 300 Pythagorean theorem. 340

Q qualifications of drivers quick-release valve, 191, 193-195, 201203,253

R radial tires, 98. 107 reaction. 241,319.337 rear axle, 6, 8, 132, 147, 216. 341-342, 393-394 rear end protection, 273 receiver, 138-139. 383 reefers, 266, 379 reflectors, 21-23, 65, 69, 73-74,275-276, 279 reflex reflector, 73-74 refrigerated vans, 265-266 relay valve, 197, 199,207-209,23 1,256 relined, 107. 301 retina. 321, 333, 383 retroreflective sheeting, 72, 74, 273 return springs, 168-169, 171 , 2 18, 223, 226,232,256,30 1

road rage, 327-328 roadway evidence, 241, 287, 348 roll center, 148, 362-363 rollers, 168-169, 218, 223, 225-226 rollover propensities, 367 rollover threshold, 112. 360-361, 366 formula, 360 rollover velocity formula, 360-361 rollovers. 4, 8. 61. 111-112. 260, 264. 266-267. 271-272, 293, 295. 300, 303, 353, 360-361' 366-367, 385, 411 rotation, 147, 185. 216, 223, 241, 293, 348,350,360 RT relay valve, 207-209 run flat, 102

s 60- or 70-hour maximum on-duty rule, 11 ,25,29,34-35,40,42 SAE paper, 220. 229 safety chains, 139 S-cam, 161.168-169,195,217-220,223224,237.242,255-256,301 effective radius, 237 schedules, 21, 125 , 313, 319, 322-323, 327 school buses,6, 70 scored drum, 170. 172 scrapes. 262. 295. 297-298, 348 scratches. 83. 295. 297-298, 315. 333, 348 secondary tank, 191, 193 self-supporting loads, 262 semi-metallic brake linings, 164 serious traffic violation, 50 service brakes, 2 I, 23, 67, 193, 200, 202, 204, 213, 2 15-216, 232, 24 1, 300301 shipper, I 6, 18, 39, 42, 245, 303, 322, 353,357 shock absorber, I06. 151 side marker lamps, 69-70, 78, 85 sidewalls, 96,98-99, 101. 103-105, 112, 315

441

Index sight distance. 274, 288 skidmarks. 44. 231. 274. 276. 287-294, 3 19.348 skip skids, 290-291, 293 slack adjuster, 161 -162, 191, 195-197, 220. 223-226, 232, 234-235, 245, 252.289.300 length, 220, 234-235 sleeper berth, 27-28, 30-32, 34-35, 3740. 42, 304-305 split, 32, 40 sliding fifth wheels, 132 specialty trailers. 270-271 speed determination from gear position, 409 speed from weight shift , 41 2 speedometer, 76, 304, 370 spider, 168- 169, 180, 2 17, 225 spring brake, 197, 199-202, 204, 208209,211,218,227,300 stationary vehicle renectors, 2 1 steering arm. 141 - 143 steering ax les, 12, I00. I02. I06, 132, 143. 195-197' 231. 237. 248-250. 255,292-293,339.341,345,347 steering components. 141 - 142, 305 steering gear, 12, 141 , 143, 305 steering shaft, 141, 143,305 steering system. 141. 143, 305 steering tires, 7, 12, 143-144 steering wheel. 12, 141. 143, 305, 3 14315 lash, 143 stiffness of the suspension, 260 stimulants, 324-325 stop lamps, 67, 70, 76, 78-79, 85-86 stoplight switch, 197- 198, 200 stopping distances, 3, 7-8, 165-166, 168, 227,240-24 1,25 1,253,264 stripped threads, 9 1, 94 super-elevation, 366-367 supply reservoir, 16 1 suppl y tank, 189, 193

suspension, 5, I I. 20, 5 I. 55, I02. I06, II 0, 141.146-148. 150. 153-157.259-260. 276,293,304,339,361,363,366 synthetic webbing, 285

T I0-hour driving time rule. II 35-mm camera, 334, 336 tachograph. 76. 304, 370-371 Tacholink onboard computer, 371 tachometer, 304, 409 tail lamps, 12, 67, 77, 84-85 tandem drive ax le, 112- 113, 154 tanker trailers, 268-269 tic rod, 8, 12, 142- 143,299,302,306 arm, 142- 143 cross tube, 142 tie-downs, 12, 264, 285 tire air pressure, 110, 237-238 construction. 97-98 damage, 107. 11 0 failure, 98. 100-10 I footprint. 408-409 identification, 96 mark, 122. 293-294, 394 pressure, 95-96,99-100,407-409 prints. 295 rolling radius. 220, 238 size, 101,110,229,394, 405 track width, 304, 340, 357, 360, 362, 365-366 tractor protection valve, 205-206, 30 I traffic accident reconstruction, 3, 411 trailer air supply valve, 205-206 conspicuity systems, 74 design, 259 "dog tracking", 145 hand control valve. 207-208 kingpin, 8, I I, 13 1-132, 134- 135, 142-143,246-249.34 1 swing. 8, II. 24 1, 255. 347-348 underride. 73-74.273,279

442 Commercial Vehicle Accident Reconstruction and Investigation tread. 94,98-101. 105. 108-111.238, 306, 407-408 depth, 238, 306 design, 407 wear, 94,98 trolley valve, 22, 107, 183, 207-208, 293,301 truck tires, 98-99. 168, 240 trucking industry, 15, 112.260, 265.276, 318,341 turbocharger, 119 two-way check valve, 197-198,200-202

u underinflated, 96,99-100, 102 un loaded vehicle weight, 7

v van trailers, 259-260, 265. 267. 359-360 vehicle dynamics. 314. 345 vehicle evidence. 299 vehicle inspection. 7. 23-24. 59. 216. 224,229,293,299,403-404.409 vehicle weights, 274 view obstruction, 115 visibi lity, 73-74,276,288,304,328,330, 332, 38 1' 383 vision, 59. 304. 320-32 1. 328. 332-334, 401

w wear, see tire wear webbing, 285

wedge, 168-169, 195,211.217-223,225. 255, 276-277. 301 -302 angles, 219-220 brakes, 217-223, 225, 255, 30 1-302 plungers, 2 19 weight at each wheel end, 240 weight of the load, 5. 229.245,248,262263,276,303.353.357-358 weight of the trailer. 245-248, 268, 284, 303-304. 357-358 weight shift. 153. 157. 166, 264, 270, 278,293,309,411-4 12 formula, 411 -4 12 wet tank, 187, 189-190, 198 wheel assembly, 13, 90-9 1, 94, I06, I08, I I 0-1 I I. 3 I 0 wheel balance, Ill wheel bearings, 8. I I0- 111. 177 wheel cylinder. 175, 211, 303 wheelbase. 240. 340-342. 347-349. 412 windshield wipers. 13. 21. 23. 332 wireless communications equipment. 379 wiring, II, 70. 77, 119. 186. 299. 303, 316,373. 387. 389

y yaw marks. 293

z zipper. 102