Safety and Mobility

Traffic medicine: safety and mobility

In the field of traffic medicine one would expect an emphasis on increasing traffic safety rather than on increasing independent mobility. As traffic injuries constitute a world-wide public health problem of staggering magnitude, sustained safety-directed efforts of professionals in medical, engineering, educational and administrative positions are essential. Nevertheless, traffic medicine also has an important role to play in facilitating independent mobility, specifically in contributing to the reduction of participation-restrictions (handicaps) and activity-limitations (disabilities) of people with functional limitations (impairments) caused by diseases, injuries and old age.

In neuropsychological practice Return to Driving is an important rehabilitation goal for brain-injured patients. Also in old age traffic mobility is extremely important for independent living and it should come as no surprise that in functionally limited older people independent mobility is an important predictor of subjective well-being.

Driving a car or riding a two-wheeler carries an increased casualty risk compared to the risk when public transport or special transport is used. This implies that rehabilitating a patient so that he or she is able to drive or ride independently – even to the safety level of the average driver- may have a negative effect on casualty risk. Presumeably no one could argue against driving rehabilitation on this basis because public transport is universally safer than driving. But what happens when the casualty risk of driving with a certain medical characteristic is higher than in the general population?

Governments have anticipated this question by specifying and enforcing fitness regulations consisting of lists of medical diagnoses and impairments thought incompatible with holding a licence or thought to require a restrained licence. From a scientific viewpoint fitness regulations can be criticized in several respects. In some cases, as for visual acuity, they prescribe very exact cut-off scores between fit and unfit drivers, which are hard to defend. In other cases – e.g. in neurological and geriatric diseases- fitness regulations are vague, leaving much room for interpretation differences and unequal treatment. Finally, the fitness regulations do not deal at all with matters of comorbidity and compensatory potential. Traffic medicine can provide a scientific basis for these regulations.

With few exceptions fitness regulations have been based on common sense and consensus of medical experts, who have been hampered by the non-availability of medically applicable theoretical models of driving performance and by lacking empirical evidence from on-road assessments of driving performance and from crash and casualty statistics.

It is time for a change. Developments in theories of driving and in neuroscience in general allow a preciser understanding of the perceptual and cognitive function requirements of driving and the neuro-behavioural effects of medical conditions. Developments in driving simulation allow theory-driven focused assessment of the effects of medical conditions and their treatments in a safe and replicable environment.

A further important mission for traffic medicine I propose is the development and evaluation of technical aids and training methods for safe independent mobility. In the last 50 years many ingenious car adaptations for compensating impairments of movement and posture have become available. However, only limited progress has been made in car adaptations and other technological aids compensating for perceptual and cognitive impairments. Computers and telecommunication hold many promises in this respect, e.g. crash avoidance systems warning drivers if they become drowsy or which alert the driver to relevant information. Also the opportunities of more conventional technology, e.g. bioptic telescopes, need to be further explored, particularly in relation to training methods. If properly developed in relation to patients’ needs and medical and psychological characteristics, rehabilitation technology could advance and extend safe independent mobility in many drivers with cognitive and perceptual impairments. Traffic medicine can play an important role in shaping these developments.

Wiebo H. Brouwer,

President of ITMA