Age-related differences in driving: Are older drivers more serial?

A measurement-instrumented car was used to test the hypothesis that older d rivers organise their car-controlling movements in a more serial way in ord er to reduce the momentary mental workload produced by complex traffic situ ations. Forty-two older drivers (65+, mean age 67.5) and 36 young middle-ag ed drivers (26-49, mean age 36.8) drove a measurement-instrumented car arou nd a 7.4km route in normal traffic. The use of car controls (e.g. clutch, b rake) was registered by sensors connected to a computer. In the most comple x parts of the test route (e.g. during which three or more controls were in use simultaneously), the older drivers tended to use three controls rather than four or more, whereas the younger group had a greater percentage of f our or more controls. This percentage was positively related to speed. Howe ver, although older drivers drove more slowly in general, in pairs matched for speed, they still drove in a less parallel manner. Irrespective of age, parallel use of controls was positively related to the level of skill as i ndicated by the amount of cumulated driving experience. The shift towards m ore serial operation of controls possibly represents an empirical demonstra tion of a compensatory mechanism allowing older drivers to maintain their l evel of performance.