This research investigates a strategy to ameliorate the largest source of unintentional injuries in the United States, motor vehicle crashes, by improving the ability of our most vulnerable drivers, the elderly, to safely negotiate the most dangerous and demanding of all traffic situations—intersections. Studies have shown that more crashes occur at intersections, resulting in more injuries and fatalities, than in any other driving situation; and this risk is exacerbated for older persons who, with their declining functional abilities but increasing frailty, represent the fastest growing segment of the driving public. Coupled with an overwhelming reliance by seniors on private vehicle travel to meet their personal mobility needs, these trends make it imperative to somehow enhance the proficiency of older drivers at intersections. The present research suggests a way to meet this goal through improvements in highway design and operations, specifically the use of the modern roundabout. Compared to conventional intersections, roundabouts have the demonstrated potential to significantly reduce the most injurious (angle) type of crashes and slow the operating speed of all vehicles, while maintaining a high capacity for moving traffic through an intersection. If all drivers, and especially older drivers, would increase their use of these highway facilities, and use them properly, a system-wide savings in traffic injuries and fatalities is a very high probability. Accordingly, this research sought to a) identify elements of roundabout design and operations that were problematic for older drivers, and b) develop recommendations and guidelines for countermeasures with the potential to improve the comfort, confidence, and safety of seniors in using roundabouts. To accomplish the objectives of this study, a series of focus groups (Phase I), in which drivers above the age of 65 provided feedback, were held to determine potential design elements at roundabouts, such as highway geometrics, traffic signs, and pavement markings that may be problematic to older drivers. Following the identification of these elements, structured interviews (Phase II), using participants in the same age group, were conducted to evaluate potential countermeasures that could be implemented for improving the comfort, confidence, and safety of older drivers who use these facilities. The results of this study show that design elements improving the path guidance of older drivers are critical for designing roundabouts. Recommendations about potential countermeasures related to advance warning signs, guide signs, yield treatment, directional signs, and exit treatment are presented. (Author/publisher)
Samenvatting