Why Are Older Drivers at Risk?
Older drivers have a higher risk of traffic fatalities for two reasons. First, drivers age 75 and older are involved in significantly more motor vehicle crashes per mile driven than middle-aged drivers. Second, older drivers are considerably more fragile than their younger counterparts, and are therefore more likely to suffer a fatal injury in the event of a crash.
The excess crash rate of older drivers results from impairments in the following functions that are important for driving:
Vision - Vision is the primary sense utilized in driving. Adequate visual acuity and field of vision are important for safe driving, but tend to decline with age as a result of physiologic changes and an increase in diseases such as cataracts, glaucoma, macular degeneration, and stroke. Glare, impaired contrast sensitivity, and an increase in time to adjust to changes in lightness and darkness are other problems commonly experienced by older drivers.
Cognition - Driving is a complex activity that requires a variety of high-level cognitive skills, including memory, visual processing, attention, and executive skills. Certain medical conditions (such as dementia) and medications that are common in the older population have a large impact on cognition.
Motor funtion - Motor abilities such as muscle strength, endurance, flexibility, and proprioception are necessary for operating vehicle controls and turning to view traffic. Even prior to driving, motor abilities are needed to enter the car safely and fasten the seatbelt. Changes related to age and musculoskeletal diseases (such as arthritis) can decrease an individual's ability to drive safety and comfortably.
Declines in these functions make older drivers vulnerable to crashes in complex situations that require good visual perception, attention, and rapid response. As a result, older drivers are more likely to experience crashes at intersections, especially when a left-hand turn is involved.