According to the National Highway Traffic Safety Administration, older drivers are more likely than drivers in their thirties, forties, or fifties to be involved in traffic crashes, and they are more likely to be killed in traffic crashes. The number of Americans 65 years of age and older is expected to double between 2000 and 2030. Americans are living longer and driving longer. Together these trends suggest that the number of older drivers killed on U.S. streets and highways will grow. The literature suggests that older drivers are more fragile than younger drivers -- that is, in crashes of comparable severity, older drivers are more likely than younger drivers to be seriously injured or killed. Medical conditions and use of medications have also been associated with the involvement of older drivers in crashes. With advancing age, sensory and motor capabilities decline and perceptual/cognitive and attentional impairment become more common, and the relative likelihood of traffic crashes increases. Although many older drivers may attempt to adjust to functional difficulties by driving less and avoiding difficult driving conditions, such as driving at night, in rainy weather, or in heavy traffic, older drivers still have a heightened risk of being involved in traffic crashes. In this study, 25 years of police-level crash data from nearly 4 million injury crashes in the state of Texas were analysed to determine the association between driver age and four factors: fragility -- the likelihood of death among drivers involved in injury crashes; illness -- the likelihood that drivers were ill or suffering from some other physical defect at the time of their crashes; perceptual lapses -- the likelihood that drivers involved in crashes failed to yield the right of way or disregarded traffic signs or signals; and left turns -- the likelihood that left turns were involved in injury crashes. The purpose of the study was to further understand these four factors and other variables and to portray in graphical format their association with crashes involving older drivers. The control variables used in the analyses included whether drivers were involved in single-vehicle or multiple-vehicle crashes; whether the crash occurred in an urban or a rural setting; the driver's sex; the light conditions at the time of the crash (daylight or darkness); and whether or not the crash was related to an intersection. Additional analyses examined two-vehicle, intersection-related crashes in which the vehicles approached one another from opposite directions or approached one another at an angle. Because older drivers do not constitute a homogeneous population, three different age thresholds were used in defining this group: 65 and older, 75 and older, and 85 and older. Drivers aged 55 to 64, those nearing traditional retirement age, constituted the comparison group in the analyses. When the analyses controlled for crash type (single-vehicle vs. multiple-vehicle), population density (rural vs. urban), driver sex (male vs. female), light condition (daylight vs. darkness), and intersection relatedness, drivers in the three older age categories, compared with drivers aged 55-64, were found to be more likely to die in injury crashes: * Drivers 65+ years of age were 1.78 times as likely to die; * Drivers 75+ years of age were 2.59 times as likely to die; * Drivers 85+ years of age were 3.72 times as likely to die. Other analyses that controlled for crash type, population density, driver sex, light condition, and intersection relatedness showed that when compared to 55-64 year old drivers, the three older age groups became progressively more likely to (1) have been ill or suffering some other physical defect at the time of their crashes, (2) have suffered perceptual lapses that contributed to their crashes (such as failure to yield the right of way or disregarding signs or signals), and (3) have been involved in left-turn crashes. (Author/publisher)
Samenvatting