Older drivers are the fastest growing segment of licensed drivers. Although older drivers are often unfairly characterized by the media as unsafe to drive, the vast majority continue to be able to drive safely. However, research reveals that medical conditions such as dementia negatively impact driving behaviour and eventually result in unfitness to drive. For example, research investigating driving performance in people with dementia indicates that:

• Driving performance decreases with increasing dementia severity.
• Type of dementia, cognitive domains most affected, medical co-morbidities, medications, and the presence of behavioural disturbances can have specific effects on driving ability.
  
  

Common domains that can make driving with dementia unsafe are:

• Increasing forgetfulness
• Limited attention span
• Limited ability to quickly process information
• Poor judgment and problem-solving ability
• Disorientation to place
• Slow reaction time
• Visual perceptual issues (manifesting with problems with sense of direction, judging distances and spead, and difficulty recognizing  objects).
  
  

As a result, dementia can pose a hazard to safe driving. Accordingly, when taking the person with dementia’s history, consider the following additional warning signs: 

• Impairment of cognitive domains as listed above.
• Driving difficulties such as observing road signs and traffic lights, lane maintenance, lane changing, turning (especially left hand turns across traffic), maintaining road speed, and merging, as well safely avoiding collisions.
• Lack of insight, leading to not being aware of, or not recognizing driving difficulties.

Some people with mild dementia may be able to drive safely for a limited time before they must stop. However, the longer a person with dementia continues to drive after diagnosis, the higher their chance of getting into a collision. The majority of studies show an increased risk of motor vehicle collisions among people with dementia.

Research indicates that driving performance decreases with increasing dementia severity (Jacobs et al., 2017). Two systematic reviews found that in 17 out of 17 studies that used driver performance as an outcome measure, drivers with dementia performed significantly worse than controls. Driving performance was evaluated using road evaluations, driving simulators and driving reports. In addition, in 6 out of 10 studies of caregiver and/or state-reported motor vehicle collisions, drivers with dementia were involved in a collision more often than controls. (Chee et al., 2017, Man-Son-Hing et al., 2007). 

Here are some opportunities for additional learning:

• Update on the risk of motor vehicle collision or driving impairment with dementia: A collaborative international systematic review and meta-analysis (The America Journal of Geriatric Psychiatry, 2017) 
• Systematic review of driving risk and the efficacy of compensatory strategies in persons with dementia (Journal of the American Geriatrics Society, 2007) (Open Access)
  
• Driving with a neurodegenerative disorder: an overview of the current literature (Journal of Neurology, 2017) (Open Access)
• Driving and dementia in Ontario: a quantitative assessment of the problem (The Canadian Journal of Psychiatry, 2004)
• Update on the risk of motor vehicle collision or driving impairment with dementia: a collaborative international systematic review and meta-analysis (The American Journal of Psychiatry, 2017)
• The driving and dementia toolkit for health professionals (The Geriatric Program of Eastern Ontario, 2009) and The driving and dementia toolkit for persons with dementia and their caregivers (The Geriatric Program of Eastern Ontario, 2011)