Long-Term Effect of Universal Helmet Law Changes on Motorcyclist Fatal Crashes: Comparison Group and Empirical Bayes Approaches

2017 ◽  
Vol 2637 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Jaeyoung Lee ◽  
Mohamed Abdel-Aty ◽  
Jung-Han Wang ◽  
Chanyoung Lee
Keyword(s):  
Empirical Bayes ◽  
Brain Injuries ◽  
Comparison Group ◽  
The United States ◽  
Regression To The Mean ◽  
Fatal Crashes ◽  
Before And After ◽  
The Law ◽  
1960S And 1970S

A motorcyclist helmet is considered important safety equipment because it prevents or minimizes head and brain injuries, which are often fatal. Hence, in the 1960s and 1970s, most of the states in the United States enacted the universal helmet law (UHL) requiring all motorcyclists to wear helmets. Many researchers have examined the effect of the helmet law changes by using before-and-after studies and found that repealing the law had a negative effect on motorcyclists. In this study, the authors have attempted to explore the long-term impacts of repeal and reinstatement of the UHL by using 13 to 16 years of data. A before-and-after study with a comparison group and empirical Bayes methods was adopted to account for the passage of time and its effect on other factors such as exposure, maturation, trend, and regression-to-the-mean bias. A range of safety performance functions was developed on the basis of counties and parishes, and the expected fatal motorcycle crashes were calculated. The results showed that the UHL repeal still had significant effects on motorcycle fatal crash counts even 7 to 12 years after the repeal of the law. The crash modification factors showed that the UHL repeal increased the number of motorcycle fatal crashes by 15% to 41%, whereas reinstatement of the UHL decreased it by 21% to 27%. It is expected that the results from this study could be helpful for state policy makers to clearly understand the effects of the UHL on reducing motorcycle fatal crashes.

National-Level Safety Evaluation of Diverging Diamond Interchanges

2019 ◽  
Vol 2673 (7) ◽  
pp. 696-708
Author(s):  
Timothy S. Nye ◽  
Christopher M. Cunningham ◽  
Elizabeth Byrom
Keyword(s):  
Empirical Bayes ◽  
Comparison Group ◽  
National Level ◽  
Group Analysis ◽  
Safety Evaluation ◽  
The United States ◽  
Group Method ◽  
Regression To The Mean ◽  
Naive Method ◽  
Diamond Interchanges

A national-level safety evaluation of Diverging Diamond Interchanges (DDIs) in the United States was completed. This study aimed to update previous evaluations and to expand the treatment group size of previous studies to provide a more robust and reliable safety assessment of DDI deployments. For this particular treatment, it was determined that, of the observational before-and-after evaluation methodologies, the comparison group approach yields the best evaluation results. The naïve method can be influenced by outside factors that cannot be accounted for (weather, crash reporting tendencies, etc.). The empirical Bayes method is unnecessary as DDIs are installed for operational benefits, meaning that risk of selection bias and regression-to-the-mean is minimal. This study recommends a total crashes crash modification factor (CMF) of 0.633 based on the comparison group analysis of 26 DDIs in 11 states. The comparison group method was also applied to a variety of crash variables for this study. Angle, rear-end, and sideswipe crashes were found to have CMFs of 0.441, 0.549, and 1.139, respectively. Fatal-and-injury crashes provided a CMF of 0.461. Daytime and nighttime crashes provided CMFs of 0.648 and 0.638, respectively.

scholarly journals Traumatic Brain Injury in Sports: A Review

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Christopher S. Sahler ◽  
Brian D. Greenwald
Keyword(s):  
United States ◽  
Traumatic Brain Injury ◽  
Cognitive Impairment ◽  
Brain Injury ◽  
Head Trauma ◽  
Brain Injuries ◽  
Cognitive Impairments ◽  
The United States ◽  
Neurological Dysfunction

Traumatic brain injury (TBI) is a clinical diagnosis of neurological dysfunction following head trauma, typically presenting with acute symptoms of some degree of cognitive impairment. There are an estimated 1.7 to 3.8 million TBIs each year in the United States, approximately 10 percent of which are due to sports and recreational activities. Most brain injuries are self-limited with symptom resolution within one week, however, a growing amount of data is now establishing significant sequelae from even minor impacts such as headaches, prolonged cognitive impairments, or even death. Appropriate diagnosis and treatment according to standardized guidelines are crucial when treating athletes who may be subjected to future head trauma, possibly increasing their likelihood of long-term impairments.

The Improbable Permanence of a Commitment: America's Troop Presence in Europe during the Cold War

2009 ◽  
Vol 11 (1) ◽  
pp. 3-27 ◽  
Author(s):  
Hubert Zimmermann
Keyword(s):  
Cold War ◽  
The United States ◽  
West Germany ◽  
Fundamental Feature ◽  
Global Policy ◽  
Long Time ◽  
1960S And 1970S ◽  
The 1960S ◽  
The Cold War

This article elucidates a fundamental feature of transatlantic relations during the Cold War: the presence of more than 250,000 U.S. troops in Europe, mainly in West Germany, from 1952 through 1990. The article explains why this unprecedented commitment was extended for such a long time, despite intense domestic debates in the United States in the 1960s and 1970s. Opposition to the troop commitment was particularly strong in Congress. The article shows that the long-term stationing of U.S. troops in Europe was more precarious than often assumed. The article also shows that the debates in the 1960s and 1970s were instrumental in establishing the acceptance of long-term military commitments abroad as a feature of U.S. global policy.

Development of Crash Reduction Factors: Methods, Problems, and Research Needs

2003 ◽  
Vol 1840 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Joan Shen ◽  
Albert Gan
Keyword(s):  
Empirical Bayes ◽  
Group Method ◽  
Research Needs ◽  
Regression To The Mean ◽  
Before And After ◽  
Safety Studies ◽  
Development Methods ◽  
Crash Reduction ◽  
Before And After Study ◽  
Reduction Factors

Crash reduction factors (CRFs) are used in highway safety studies to predict safety benefits due to reduced numbers of crashes. NCHRP Report 162 identified the need for the development of a national comprehensive set of CRFs for each state to evaluate safety improvements. However, this need has not been met. As a result, many states have developed their own CRFs or have adopted CRFs from other states. A synthesis of the CRF development methods, the associated problems, and the research needs are provided. The emphasis is placed on the before-and-after study method because it has been, and still is, the method of choice for CRF development. Three before-and-after study methods were introduced and reviewed: ( a) the simple before-and-after method, ( b) the before-and-after study with comparison group method, and ( c) the before-and-after study with the empirical Bayes method. The problems associated with the simple before-and-after studies, including regression to the mean, crash migration, maturation, and external causal factor, are discussed. Several research needs related to crash migration and general CRF development are also identified. The information presented in the synthesis will be useful to states that plan to develop or update their CRFs.

Assessing the Capability of Helmets to Prevent Concussion: Principles and Applications of the STAR Evaluation System

2012 ◽  
Author(s):  
Steven Rowson ◽  
Stefan M. Duma
Keyword(s):  
United States ◽  
Evaluation System ◽  
Brain Injuries ◽  
Essential Element ◽  
The United States ◽  
Health Concern ◽  
Primary Health ◽  
Head Protection ◽  
New Research

Research has estimated that between 1.6 and 3.8 million sports-related concussions are sustained in the United States each year [1]. In light of new research suggesting that potential long-term neurodegenerative effects can result from repetitive brain injuries, concussions have been placed under the national spotlight as a primary health concern. While minimizing the exposure of athletes to head impact is one important component of reducing the incidence of concussion, improvement in head protection is another essential element. This paper focuses on a new mechanism to evaluate the protective capabilities of helmets in relation to concussion.

Part V Case Studies, 42 The Japan Experience with Visiting Forces—An Evolving Perspective

2018 ◽  
Author(s):  
Kawai Junya ◽  
Sonnenberg Dale L ◽  
Timm Donald A
Keyword(s):  
United States ◽  
Everyday Life ◽  
Case Studies ◽  
The United States ◽  
Global Strategy ◽  
Security Treaty ◽  
The Us ◽  
The Status ◽  
The Law

This chapter considers Japan’s experience with visiting forces. Unlike the NATO experience in Europe, the United States and Japan had very different backgrounds and cultures. The long-term stationing of US forces in Japan is remarkable because despite the circumstances under which it began, it grew into a partnership of allies and equals. The US-Japan Security Treaty and its successor, and the agreements thereunder regarding the status of forces, as main instruments of the law of visiting forces in Japan have been utilized flexibly to meet the defence and security needs of Japan and the security needs of the United States from the standpoint of fulfilling its regional commitments and its global strategy. However, the application of these treaties and agreements has been influenced not only by military convenience, but also by the interest to achieve harmonization with everyday life of residents in Japan.

Traffic Conflict–Based Before–After Study with Use of Comparison Groups and the Empirical Bayes Method

2017 ◽  
Vol 2659 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Passant Reyad ◽  
Emanuele Sacchi ◽  
Shewkar Ibrahim ◽  
Tarek Sayed
Keyword(s):  
Road Safety ◽  
Empirical Bayes ◽  
Comparison Group ◽  
Treatment Effectiveness ◽  
Video Data ◽  
Safety Performance ◽  
Group Method ◽  
Safety Level ◽  
Before And After ◽  
Traffic Conflict

Road safety evaluations mainly rely on the analysis of crash data that are challenged by well-recognized availability and quality issues. The statistical models used to predict the safety level of road sites—that is, safety performance functions—have recently been successfully developed with the use of traffic conflict observations instead of crashes. As such, it is possible to adopt and transfer the statistical techniques used in crash-based road safety analysis to conflict-based analysis. The use of statistically rigorous techniques in crash-based before-and-after (BA) studies is essential for evaluation of the effectiveness of road safety countermeasures. In particular, the use of Bayesian methods, such as the empirical Bayes (EB) technique, is vital to control for confounding factors that can operate simultaneously with the countermeasure and may affect road safety performance. The main objective of this paper was to estimate the treatment effectiveness of two traffic signal (visibility) improvement projects in the city of Edmonton, Alberta, Canada, with a conflict-based BA study using the comparison group and the EB methods. More than 300 h of video data with traffic conflict observations was automatically collected and analyzed by computer vision techniques for two treatment intersections and two control (untreated) intersections before and after the signal improvement projects. The results of the comparison group method showed a statistically significant 24% reduction in the average number of rear-end conflicts per hour, whereas the EB method showed a statistically significant 24.5% reduction in the average number of total conflicts per hour.

Racism Is Not Enough: Minority Coalition Building in San Francisco, Seattle, and Vancouver

2020 ◽  
Vol 34 (2) ◽  
pp. 195-215 ◽  
Author(s):  
Jae Yeon Kim
Keyword(s):  
United States ◽  
San Francisco ◽  
Minority Groups ◽  
Historical Analysis ◽  
The United States ◽  
Coalition Building ◽  
Exogenous Shocks ◽  
1960S And 1970S ◽  
The 1960S

Scholars have long argued that the marginalized racial status shared by ethnic minority groups is a strong incentive for mobilization and coalition building in the United States. However, despite their members’ shared racial status as “Orientals,” different types of housing coalitions were formed in the Chinatowns of San Francisco, Seattle, and Vancouver during the 1960s and 1970s. Asian race-based coalitions appeared in San Francisco and Seattle, but not in Vancouver, where a cross-racial coalition was built between the Chinese and southern and eastern Europeans. Drawing on exogenous shocks and process tracing, this article explains how historical legacies—specifically, the political geography of settlement—shaped this divergence. These findings demonstrate how long-term historical analysis offers new insights into the study of minority coalition formation in the United States.

scholarly journals The Annual Cannabis Holiday and Fatal Traffic Crashes

2019 ◽  
Author(s):  
Sam Harper ◽  
Adam Palayew
Keyword(s):  
United States ◽  
Rate Ratio ◽  
Reporting System ◽  
Incidence Rate Ratio ◽  
The United States ◽  
Traffic Crashes ◽  
Impaired Driving ◽  
Fatal Crashes ◽  
Before And After ◽  
The Impact

Background: Cannabis use has been linked to impaired driving and fatal accidents. Prior evidence suggests the potential for population-wide effects of the annual cannabis celebration on April 20th ("4/20"), but evidence to date is limited.Methods: We used data from the Fatal Analysis Reporting System for the years 1975-2016 to estimate the impact of "4/20" on drivers involved in fatal traffic crashes occurring between 1620h and 2359h in the United States. We compared the effects of 4/20 to those for other major holidays, and evaluated whether the impact of "4/20" had changed in recent years. Results: Between 1992-2016 "4/20" was associated with an increase in the number of drivers involved in fatal crashes (Incidence rate ratio [IRR]: 1.12, 95% CI 0.97 to 1.28) relative to control days one week before and after, but not when compared with control days one and two weeks before and after (IRR 1.05, 95% CI 0.92 to 1.28) or all days of the year (IRR 0.98, 95% CI 0.88 to 1.10). Across all years we found little evidence to distinguish excess drivers involved in fatal crashes on 4/20 from routine daily variations. Conclusions: There is little evidence to suggest population-wide effects of the annual cannabis holiday on the number of drivers involved in fatal traffic crashes.

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