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Traffic management and collision investigation
1X6
Recent
Publications
investigator. Certainly, this is an area of crash investigation that has in the past tended towards art over science. With the advent of computer programs to assist in crash reconstruction there has been great improvement in this area. Though there is mention in the book that computerized crash reconstruction programs do exist, they are not discussed at any length. This is a relatively serious shortcoming since such programs are accessible through government sources and probably should be a tool used by those who do any extensive crash reconstruction work. On balance though, these sections of the book are well done. Theories and principles discussed in the earlier sections are shown in meaningful application. These sections, as well as the rest of the book, are clearly and concisely written in a non-technical language. The next chapter deals with what are called “human aspects.” The main areas covered are (I) perception and reaction times and (2) chain collisions, which is largely a discussion of queueing theory. The major focus of the book, written by engineers and/or physicists, is understandably about the mechanics of crashes with particular emphasis on the vehicles. However, any discussion of the human element should address such areas as alcohol involvement and other potential contributing factors such as distractions, physical condition, man/machine compatibility and the like. These are not covered. If one feels that the three part typology of crashes (driver, vehicle and environment) is an important one, one would also be distressed that the road and roadside environment does not receive a more full treatment. Certainly various roadside appurtenances, roadway geometry and the like warrant a fuller discussion. The final chapter contains a number of practical pointers on actually conducting the investigation including such elements as photographic techniques, note taking and sketching the scene. One additional missing element that I would think useful in a book of this type would be a summary section containing most frequently used formulae and tables presented elsewhere in the book. Though I am somewhat critical of the short shrift offered the human and environmental aspects of crashes, vehicular aspects are well covered and the book is certainly well written (there is no evidence that it is the product of a committee) and should prove to be a useful text or manual for accident investigators. JOHN H. LACEY
University of North Carolina Highway Safety Research Center REFERENCES Dare C. E., Owens J. C. and Krane S. Impacl of Motorcycle Helmet Usage in Colorado. Execufice Summnry. Colorado Department of Highways, 1978. (DOT HS-803 679). Lynn C. W. Repeal and Modification of Mandatory Motorcycle Helmet Legislation. A Review of Available Information. Virginia Highway and Transportation Research Council, Charlottesville, Virginia, 1978.
Traffic Management and Collision Investigation: Warren Cliffs, New Jersey, 1982. 332 pp.
E. Clark. Prentice-Hall,
Englewood
The book starts with a historical perspective of traffic problems before the time of Christ. Following chapters cover traffic accident investigation and reconstruction, human factors, collision statistics, traffic supervision, enforcement techniques and other topics. The author has attempted to cover too many subjects; hence much of the discussion is says little about data needed for superficial. For example, the chapter “Collision Investigation” trafhc accident reconstruction; specifically details on how measurements should be made are lacking. Comments on braking and examination of vehicle lamps for on/off are definitely misleading. The chapter on collision reconstruction is particularly disappointing. A number of statements are made which are not totally accurate. In other cases, there are serious errors. An example will illustrate. The term “vault” is used to describe the equation for a simple fall from one level to another instead of identifying it with the equation for a flip, the vault being an
187
Receni Publications
end-over-end flip. Furthermore, the statement is made that the equation for a fall “holds true for a ditch.. . with a slope of approximately 45”,” whereas the fall equation applies regardless of slope. The 45” angle applies to that assumed for takeoff in a hip or vault, not in a fall. Some of the errors are unexplainable. The equation for computing radius from chord and middle ordinate is correct, but the nomograph representing this equation has the middle ordinate line mislabelled as “centimeters and meters” whereas the lines for chord and radius are in feet. Much of the data is derived from various sources but none of these is identified. It would be helpful, for example, if the equation for hydroplaning were accompanied by some clue as to ivho originated it so that the reader could pursue the matter further if he wished. In summary, it is difficult to recommend this book. My area of review concentrated on traffic accident investigation and reconstruction. In these areas, other texts cover these subjects considerably better. LYNN B. FRICKE The Trafic Institute Northwestern University
Methods for Evaluating Road Safety Measures: OECD Road Research Group. Organization Economic Co-operation and Development, 1981. 108 pp. $7.50.
for
This book of about one hundred pages maintains the high standard of publication which I for one have come to expect from the OECD Road Research Group. Published in June, 1981, by a project team with representatives from 15 of the 24 OECD member countries, the report represents a valuable state of the art review. The primary aim of the Research Group was “to make recommendations of appropriate techniques for the assessment of the effectiveness of safety measures and determination of their relative priorities.” Eight chapters and two appendices review the findings. The introductory first chapter outlines the background to the project and its objectives. In establishing the need to develop effective evaluation techniques the point is made that systematic statistical and economic evaluations of safety measures are rare, while the literature abounds with examples of inadequate or inappropriate evaluations. The Group (with stated justification) specifically avoided producing a comprehensive catalogue of results of evaluations and this may disappoint some policy analysts looking for simple numbers to plug into equations. The second chapter briefly discusses the road accident problem and introduces a classification of possible solutions. The chapter concludes rather abruptly but this did not matter much since I saw it more as an extension to the background rather than a major’ component of the central thesis. Chapter 3 addresses the fundamental questions of the criteria by which accident problems are identified and by which effectiveness is assessed. The difficulty in obtaining reliable accident data is highlighted as is the increasing trend to use intermediate criteria of various types. Because few intermediate variables have been reliably correlated to accident frequency, caution should be exercised in using them to quantify safety benefits. This area needs further study. Chapters 4 and 5 focus on evaluation methods. The former deals with techniques to determine effectiveness of safety measures and the latter with techniques of economic evaluation to determine priorities for the allocation of resources among measures. Chapter 6 discusses the evaluation procedures used in member countries and also the costing of accidents and casualties. Recommendations are summarised in Chapter 7 and future research suggestions in Chapter 8. Appendix A presents some examples of evaluations which have been completed in member countries. At a time when most countries are struggling to find the best way of using scarce resources this report is timely. It does not attempt to play down the difficulties of meaningful evaluation but does identify areas where research is needed to produce information which will minimize these difficulties.
Recent
Publications
investigator. Certainly, this is an area of crash investigation that has in the past tended towards art over science. With the advent of computer programs to assist in crash reconstruction there has been great improvement in this area. Though there is mention in the book that computerized crash reconstruction programs do exist, they are not discussed at any length. This is a relatively serious shortcoming since such programs are accessible through government sources and probably should be a tool used by those who do any extensive crash reconstruction work. On balance though, these sections of the book are well done. Theories and principles discussed in the earlier sections are shown in meaningful application. These sections, as well as the rest of the book, are clearly and concisely written in a non-technical language. The next chapter deals with what are called “human aspects.” The main areas covered are (I) perception and reaction times and (2) chain collisions, which is largely a discussion of queueing theory. The major focus of the book, written by engineers and/or physicists, is understandably about the mechanics of crashes with particular emphasis on the vehicles. However, any discussion of the human element should address such areas as alcohol involvement and other potential contributing factors such as distractions, physical condition, man/machine compatibility and the like. These are not covered. If one feels that the three part typology of crashes (driver, vehicle and environment) is an important one, one would also be distressed that the road and roadside environment does not receive a more full treatment. Certainly various roadside appurtenances, roadway geometry and the like warrant a fuller discussion. The final chapter contains a number of practical pointers on actually conducting the investigation including such elements as photographic techniques, note taking and sketching the scene. One additional missing element that I would think useful in a book of this type would be a summary section containing most frequently used formulae and tables presented elsewhere in the book. Though I am somewhat critical of the short shrift offered the human and environmental aspects of crashes, vehicular aspects are well covered and the book is certainly well written (there is no evidence that it is the product of a committee) and should prove to be a useful text or manual for accident investigators. JOHN H. LACEY
University of North Carolina Highway Safety Research Center REFERENCES Dare C. E., Owens J. C. and Krane S. Impacl of Motorcycle Helmet Usage in Colorado. Execufice Summnry. Colorado Department of Highways, 1978. (DOT HS-803 679). Lynn C. W. Repeal and Modification of Mandatory Motorcycle Helmet Legislation. A Review of Available Information. Virginia Highway and Transportation Research Council, Charlottesville, Virginia, 1978.
Traffic Management and Collision Investigation: Warren Cliffs, New Jersey, 1982. 332 pp.
E. Clark. Prentice-Hall,
Englewood
The book starts with a historical perspective of traffic problems before the time of Christ. Following chapters cover traffic accident investigation and reconstruction, human factors, collision statistics, traffic supervision, enforcement techniques and other topics. The author has attempted to cover too many subjects; hence much of the discussion is says little about data needed for superficial. For example, the chapter “Collision Investigation” trafhc accident reconstruction; specifically details on how measurements should be made are lacking. Comments on braking and examination of vehicle lamps for on/off are definitely misleading. The chapter on collision reconstruction is particularly disappointing. A number of statements are made which are not totally accurate. In other cases, there are serious errors. An example will illustrate. The term “vault” is used to describe the equation for a simple fall from one level to another instead of identifying it with the equation for a flip, the vault being an
187
Receni Publications
end-over-end flip. Furthermore, the statement is made that the equation for a fall “holds true for a ditch.. . with a slope of approximately 45”,” whereas the fall equation applies regardless of slope. The 45” angle applies to that assumed for takeoff in a hip or vault, not in a fall. Some of the errors are unexplainable. The equation for computing radius from chord and middle ordinate is correct, but the nomograph representing this equation has the middle ordinate line mislabelled as “centimeters and meters” whereas the lines for chord and radius are in feet. Much of the data is derived from various sources but none of these is identified. It would be helpful, for example, if the equation for hydroplaning were accompanied by some clue as to ivho originated it so that the reader could pursue the matter further if he wished. In summary, it is difficult to recommend this book. My area of review concentrated on traffic accident investigation and reconstruction. In these areas, other texts cover these subjects considerably better. LYNN B. FRICKE The Trafic Institute Northwestern University
Methods for Evaluating Road Safety Measures: OECD Road Research Group. Organization Economic Co-operation and Development, 1981. 108 pp. $7.50.
for
This book of about one hundred pages maintains the high standard of publication which I for one have come to expect from the OECD Road Research Group. Published in June, 1981, by a project team with representatives from 15 of the 24 OECD member countries, the report represents a valuable state of the art review. The primary aim of the Research Group was “to make recommendations of appropriate techniques for the assessment of the effectiveness of safety measures and determination of their relative priorities.” Eight chapters and two appendices review the findings. The introductory first chapter outlines the background to the project and its objectives. In establishing the need to develop effective evaluation techniques the point is made that systematic statistical and economic evaluations of safety measures are rare, while the literature abounds with examples of inadequate or inappropriate evaluations. The Group (with stated justification) specifically avoided producing a comprehensive catalogue of results of evaluations and this may disappoint some policy analysts looking for simple numbers to plug into equations. The second chapter briefly discusses the road accident problem and introduces a classification of possible solutions. The chapter concludes rather abruptly but this did not matter much since I saw it more as an extension to the background rather than a major’ component of the central thesis. Chapter 3 addresses the fundamental questions of the criteria by which accident problems are identified and by which effectiveness is assessed. The difficulty in obtaining reliable accident data is highlighted as is the increasing trend to use intermediate criteria of various types. Because few intermediate variables have been reliably correlated to accident frequency, caution should be exercised in using them to quantify safety benefits. This area needs further study. Chapters 4 and 5 focus on evaluation methods. The former deals with techniques to determine effectiveness of safety measures and the latter with techniques of economic evaluation to determine priorities for the allocation of resources among measures. Chapter 6 discusses the evaluation procedures used in member countries and also the costing of accidents and casualties. Recommendations are summarised in Chapter 7 and future research suggestions in Chapter 8. Appendix A presents some examples of evaluations which have been completed in member countries. At a time when most countries are struggling to find the best way of using scarce resources this report is timely. It does not attempt to play down the difficulties of meaningful evaluation but does identify areas where research is needed to produce information which will minimize these difficulties.