Traffic fatalities and injuries: the effect of changes in infrastructure and other trends (original) (raw)
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Accident Analysis & Prevention, 2004
This paper presents an analyses of data from the Highway Safety Information System (HSIS) for the State of Illinois. Our analyses focuses on whether various changes in road network infrastructure can be associated with changes in road fatalities and reported accidents. We also evaluate models that control for demographic changes. County-level time-series data is used and fixed effect negative binomial models are estimated. Results cannot confirm the hypothesis that changes in road infrastructure have been beneficial for safety. Increases in the number of lanes and increased lane widths appear to increase traffic-related fatalities.
Journal of Transportation Safety & Security, 2012
This paper uses aggregate data from the World Health Organization (WHO) and the International Road Federation (IRF) to identify the relationship between aggregate levels of road traffic safety, health service levels, motorization level, and associated factors. Two alternative modeling specifications are used to estimate the national fatality rate, number of hospital beds, and the number of registered vehicles per capita. The first specification is a system of seemingly unrelated regression equations (SURE) while the second is a set of regression models. The results suggest that a number of socio-economic explanatory factors, government laws and policies and their enforcement levels, and traffic and geographic characteristics, are significantly related to the three response variables. The paper shows that the SURE model is statistically superior to the separately-estimated regression models. The model findings are exploratory, but can still offer preliminary insights to planners to identify the extent to which traffic and motorization levels, regional and geographic characteristics, and most importantly, existing traffic laws and policies can influence traffic fatalities.
Accident Analysis & Prevention, 2015
The number of traffic fatalities reached a peak in many highly motorised countries around 1970. Some previous studies have suggested that the turning point in the number of traffic fatalities was inevitable and did not reflect a change in the underlying trends influencing the number of traffic fatalities. Other studies suggest that trends in traffic growth and fatality rate changed from before to after the turning point. This paper proposes two hypotheses about the turning point in the number of traffic fatalities. One hypothesis is that the long-term trends in traffic growth and fatality rate were the same before and after the turning point. The other hypothesis is that the long-term trends in traffic growth and fatality rate were different before and after the turning point was reached, in particular that the annual percentage decline in fatality rate became greater after the turning point than before. Such a change would suggest that road safety policy became more effective. Analysis of data for six countries (Denmark, Great Britain, Netherlands, Norway, Sweden, United States) lends stronger support to the latter hypothesis than to the former. The lesson for policy makers, in particular in countries where the number of traffic fatalities is still growing, is that they should not expect a turning point to be reached without policy interventions.
THE EFFECT OF SEAT BELT USAGE RATES ON THE NUMBER OF MOTOR VEHICLE-RELATED FATALITIES
The effectiveness of seat belt usage in reducing mortality and morbidity among traffic accident victims has been well established. Population usage rates have been increasing from eleven percent in 1980 to sixty-eight percent in 1995, as measured by observational surveys sponsored by the National Highway Traffic Safety Administration (NHTSA). Safety incentive grants from NHTSA to the States with higher than average usage rates are expected to total $500 million during 1999 -2003. Longitudinal annual motor vehicle-related fatality levels are analyzed by state to estimate the effect of the population seat belt usage rate on fatalities in the presence of known confounders such as alcohol use and youthful drivers. Consideration of alternative multivariate methodologies applied to fifteen years of data shows that the population usage rate is associated with a small effect on fatalities that for most methodologies is not statistically significant. Such a result calls into question the NHT...
Death and Injury from Motor Vehicle CrashesA Tale of Two Countries
American Journal of Preventive Medicine, 2005
To determine why road deaths dropped by 33.9% in the United Kingdom, compared to 6.5% in the United States, between 1990 and 1999. Methods: Deaths per billion vehicle kilometers traveled (D/BVKM), and case fatality rates (CFR) in the United States and the United Kingdom were tracked. Time trends in CFR can be used to track the direct effects of speed of impact. CFR is a crash-phase outcome that is independent of exposure, and varies approximately to the fourth power of the speed of crash impact. Joinpoint regression analysis was used to analyze changes in time trends of CFR. Results: In the 1990s, the decrease in deaths in the United Kingdom was attributable mostly to the 29.6% drop in the CFR. In the United States, the CFR dropped by only 6.6%. The United Kingdom introduced speed cameras and an array of speed-calming measures. By contrast, in the United States, use of speed cameras was extremely rare, and speed limits and speeds increased in 32 of the 50 states, mostly in 1995 and 1996, after which CFR actually rose (p Ͻ.0001). Intercountry differences in time trends in seat belt use, trauma care, vehicle kilometers traveled, congestion, and driving under the influence of alcohol (DUI), along with massive increase in use of higher-risk sports utility vehicles in the United States, did not account for the contrasting trends in deaths through the 1990s. But increases in DUI in the United States after 1997 may have contributed to increases in speed-related crashes. Conclusions: The reductions in CFR, probably from small drops in speed of impact account for the disproportionately greater drop in death tolls in the United Kingdom compared to the United States. The temporal fit between drops in CFR and deaths following the introduction of speed cameras in the United Kingdom and increases in speed (speed creep), CFR, and deaths in the United States following raised speed limits suggests that diverging changes in speeds of impact accounted mainly for these changes. Use of D/BVKM to correct for exposure concealed the lack of progress after 1990 in the United States, since falling time trends in D/BVKM reflect increases in congestion. If the United States had implemented United Kingdom-type speed control policies and not raised speed limits, there would have been an estimated 6500 to 10,000 (ϳ16% to 25%) fewer road deaths per year during the period following speed-limit increases (1996 to 1999), including many DUI-related deaths. Reductions of up to 50% are now achievable based on newer population-wide strategies for speed control.
Effects of Increased Auto Safety Belt Use Levels on Fatalities
Risk Analysis, 1992
To reduce the annual toil of highway deaths, more than 30 states have passed laws mandating the use of safety belts. All have been effective at raising safety belt use; equipped with different provisions and enforced with unequal care, however, they have done so to different degrees. The article estimates the relationship between attained belt use and fatalities averted. Monthly 1982-1986 fatality, collision, belt use, and other data from 64 areas in nine states were collected, then analyzed using a Poisson multiple regression model. The analysis indicates that an increase in belt use from 1440% averts about 13% of fatalities; a more pronounced increase to 50% averts about 18%. An increase from 5&75% averts about 16% of remaining fatalities. Three significant conclusions emerge. First, previous estimates appear to have understated, in general, the overall effectiveness of belt use laws. Second, the benefits of programs to boost safety belt use in this country from its current level of about 50% to up to 75%, estimated on the basis of more direct evidence from U.S. data than previously available, appear to be very large. Third, Poisson and other multiple regression models including explicit allowance for other causal factors can usefully complement other statistical approaches in traffic safety studies.