Speed and acceleration patterns of younger and older drivers
Porter, Michelle M.
Canadian Multidisciplinary Road Safety Conference
Driving and aging is an area that is receiving more research attention. Most studies have been epidemiological or laboratory-based. Few studies have examined in-vehicle performance, and those that do usually rely on the subjective evaluation of an observer inside or outside the vehicle. The purpose of this study was to examine driver-induced vehicle longitudinal movements under real life conditions in younger (30 - 50 years) and older ($70 years) men and women. It was hypothesized that both the younger drivers and the male drivers would show higher speed and acceleration related values. A total of 49 drivers (13 younger men, age 37.8 ± 5.9; 12 younger women, age 40.2± 7.1; 13 older men, age 76.0 ± 4.6; and 11 older women, age 76.7 ± 5.5) drove a 26 km road course which included residential, collector, arterial and highway roads with 30 intersections. The vehicle movement data were collected by a Global Positioning System (GPS) receiver which was installed in each subject’s own vehicle. In addition, the scene in front of the driver was captured using a digital video camera, without the image of the driver, to provide context for the GPS data. The following maximum speed data were analysed: 1) the whole road course, 2) within all the sections between the 30 intersections and 3) within all the sections between the 12 stop signs. The acceleration and the deceleration data were analysed only between the stop sign intersections because of the consistent speed limits on these sections (50 km/hr). The data were then statistically analysed between the age and the gender groups by multivariate analysis of variance/covariance. Results showed that there were age differences for maximum speeds, for all three analyses (i.e., whole road course, all sections, stop sign sections), with the younger drivers having faster speeds than the older drivers. Acceleration results showed that older drivers accelerated over a longer distance than younger drivers, and that older female drivers had less deceleration over a longer distance than younger female and older male drivers. It is concluded that age group differences exist for speed and acceleration, under real-world conditions. The current study’s results have implications for road safety because previous studies have concluded that drivers with crashes had higher maximum speeds and accelerations than drivers with no crash record.