Accident; analysis and prevention
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Two field experiments were conducted to establish the most effective method of enforcement in reducing driving speed and to establish the most efficient strategy in terms of police force personnel required. In the first experiment, the effect of three variables on driving speed on motorways was studied. The first variable, intensity of enforcement, was manipulated by creating three different objective levels of apprehension for detected speeding drivers. ⋯ The questionnaire surveys indicated that most drivers did not notice the recurrence in enforcement activities due to infrequent passing of the sections of motorways studied. The preventive effect of police enforcement appeared to be far more substantial than its repressive effect. Enforcement primarily deters the current nonoffender from speeding.
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Comparative Study
Driver injury and fatality risk in two-car crashes versus mass ratio inferred using Newtonian mechanics.
This paper aims at explaining the results of a recent empirical study that found that when cars of unequal mass crash into each other, the ratio of driver fatality risk in the lighter care to risk in the heavier car (the fatality risk ratio) increased as a power function of the ratio of the mass of the heavier car to that of the lighter car (the mass ratio). The present study uses two sources of information to examine the relationship between these same quantities: first, calculations based on Newtonian mechanics, which show that when two cars crash head-on into each other, the ratio of their changes in speed (delta-v) is inversely proportional to mass ratio; second, National Accident Sampling System data, which show how delta-v affects driver injury risk. ⋯ Combining the two sources of information gives the result that fatality risk ratio increases as a power function of mass ratio, the same functional form found in the empirical study. Because the study is rooted in Newtonian mechanics, it clearly and directly identifies physical mechanisms involved and leads to the conclusion that mass, as such, causes large differences in driver injury and fatality risk when cars of unequal mass crash into each other.
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Bicycling injury results in about 580,000 emergency room visits and 900 deaths each year in the United States. Alcohol involvement in bicycling injury has not been well documented in the literature. Using data from the Fatal Accident Reporting System, blood alcohol concentrations (BACs) among fatally injured bicyclists ages 15 years or older were examined for the years 1987-1991. ⋯ Even among decedents aged 15-19, who were legally prohibited from drinking, 14% had positive BACs. Further studies are needed to confirm the causal relationship between alcohol use and bicycling injury and to better understand the factors related to drinking and biking. The role of alcohol should be seriously considered in developing strategies of bicycling injury control and prevention.
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Alcohol use, driving records, crash culpability, and crash conviction rates for 165 injured motorcycle drivers (MTCDs) were studied. Of the 165 MTCDs, 53.3% tested positive for alcohol (BAC+). ⋯ Of the surviving culpable impaired MCTDs (n = 48), 16.7% received crash-related convictions, 12.5% received alcohol-related convictions. The reasons for the low conviction rates are probably multifactorial.
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A study was conducted to evaluate mobile roadside speedometers as a means of controlling urban traffic speeds under varied schedules of deployment and speed limit law enforcement. Speeds of cars passing the roadside speedometer were measured using nondetectable radar. ⋯ However, the effect of the speedometer was limited to the times when it was actually deployed. Associated police enforcement is a key factor, as the effect of the speedometer decayed over time but could be long lasting with a minimal amount of enforcement activity in the area of the speedometer.