WebStopping sight distance. Urban Arterial: urban arterials with speeds 45 mi/h (70 km/h) or
Although the total number of crashes was reduced at unsignalized intersections that contained signs when compared with unsigned intersections, the crash involvement ratios of aging drivers were higher at signed intersections than at unsigned intersections. In terms of the frequency of injury at unsignalized intersections, rear-end crashes were the most frequent cause (35 percent), followed by right-angle crashes (18 percent), other-angle crashes (10 percent), and head-on/left-turn crashes (8 percent). In the 1990Green Book, the issue was addressed at the end of the Case III discussions in two paragraphs. Just over 20 percent indicated that finding a side road was not a problem for them. Other studies have attempted to show the benefits to be gained from improvements to ISD (Mitchell, 1972; Strate, 1980). Many aging drivers experience a decline in head and neck mobility, which accompanies advancing age and may contribute to the slowing of psychomotor responses. (2007) concluded that, based on the simulation results, conventional arrow signs and markings, fishhook signs and markings, or lane restrictions included on diagrammatic navigation signs would be equally effective, however, additional steps may be needed to achieve a higher rate of compliance where lane restriction compliance is deemed important for either operations or safety. The available sight distance on a roadway should be sufficiently long enough The mean walking speed for females age 66 and older was 3.28 ft/s. Using these results, predicted crash reduction frequencies related to ISD were derived as shown inTable 13. Maximum lateral acceleration approached significance with greater values for the unimproved intersection (indicating poorer lateral control during the turn). The sample included 101 intersections with at least one intersecting roadway with a speed limit of 45 mph or higher. Signing countermeasures to improve safe operation by aging drivers at stop- and yield-controlled intersections follow. However, approximately one-fifth of the aging drivers participating in focus group studies conducted by Staplin, et al. The lower percentage of nighttime crashes of aging drivers may be due to a number of factors, including reduced exposureaging drivers as a group drive less at nightand a self-regulation process whereby those who do drive at night are the most fit and capable to perform all functional requirements of the driving task (National Highway Traffic Safety Administration, 1987).