Driving assessment and driving behaviour

Introduction Driving is an important part of everyday life and represents independence. Activities, both productive and social, may be affected if a person can no longer drive. Older drivers, as a group, have a low crash rate. On the other hand, driving may be affected by medical conditions in this group, for example dementia or stroke, which often call into question a person’s fitness to drive. However, there are older drivers who may benefit from compensatory strategies to prevent driving cessation. Aim The aim of the thesis was to examine driving assessments methods, both off-and on-road tests, and if an intervention may improve driving behaviour for older adults. The specific aims were to: examine how occupational therapists (OTs) are involved in driving assessments in Sweden, what methods are used and how these assessments are performed; determine whether the commonly used cognitive test battery, the NorSDSA, could predict an on-road test results for stroke and cognitive deficits/dementia participants; investigate driving errors characteristic in older drivers without cognitive impairments and identify relationships between off-road and on-road tests results; investigate whether automatic transmission, compared with manual transmission, may improve driving behaviour of older and younger drivers. Methods In Study I, a questionnaire was sent to 154 geriatric, rehabilitation and neurological clinics and additionally directly to 19 OTs. In Study II, data consisted of test results from 195 clients who had completed a fitness to drive assessment. In Study III, 85 older volunteer drivers were assessed regarding their vision, cognition and driving behaviour. In Study IV, 31 older drivers and 32 younger drivers were assessed twice on the same fixed route; once in a car with manual transmission and once in a car with automatic transmission. Results Driving assessments were carried out by OTs in various manners and diverse methods were used. Most OTs used off-road tests; tests developed specifically for driving assessments or un-standardised activity assessments. Even though few off-road tests can predict driving performance, only 19 % of the OTs used on-road test. The off-road test NorSDSA could neither predict an outcome of an on-road test for stroke clients, nor for cognitive deficits/dementia clients. Some of the older volunteer drivers displayed questionable driving behaviour, although they were fit to drive and a total of 21 % failed the on-road test. Using automatic instead of manual transmission was shown to improve older, but not younger drivers’ driving behaviour. Conclusions For OTs in Sweden, driving assessments are challenging, since there are no specified guidelines regarding the appropriate assessment tools. Assessors often solely rely on cognitive test(s) when assessing their clients. NorSDSA should not be used as a stand-alone test when determining fitness to drive. The lack of guidelines can be problematic for OTs, but also for the clients, since there is a risk that they do not receive a valid and reliable assessment. To perform these kinds of assessments there is a need for specialised training. On-road assessments are seen as the gold standard but that standard needs to encompass driving problems or errors that are “normal” driving behaviours in older persons. To switch from manual to automatic transmission may be a way to assist older drivers to continue driving and maintain the quality of their transport mobility