Community Research and Development Information Service - CORDIS

Route management systems and car telephones-behavioural effects on drivers

It was decided to concentrate on 2 in-vehicle applications, route navigation systems and hands free car phones. Whilst the emphasis of the project was the testing of data capture tools through hands on experience of usability evaluation, it was necessary for the project to undertake a number of background, literature reviews. 2 of these attempted to formulate driver information needs and the impact of man machine interaction (MMI) with route navigation technology, on the basis of cognitive models of human information processing. Another defined the requirements for task complexity in real road field trials. A fourth provided a critique and summary of psychophysiological investigation of driver behaviour. This research lays particular emphasis on the pragmatic constraints and problems of using these measures within the context of a real road trial. These reviews provided vital background material for the real road trials on route navigation.
The development of a multilevel approach to system evaluation took the form of 2 parallel strands of investigation, real road trials and dynamic simulator trials. The project performed 5 studies investigating changes in driver behaviour due to hands free carphone use. 2 of these studies were performed on the real road and the rest in the dynamic simulator.
Normal driving (ie driving in silence) was compared to driving and performing a verbal secondary task via either a hands free carphone or to an experimental stooge sat in the passenger seat. This approach was particularly use for the detection of different patterns of braking behaviour. This study was also notable in that the psychophysiological variable (in this case, mean heart rate) was demonstrated to differentiate between the two verbal secondary tasks.
Whilst real road studies were directed toward detecting subtle changes in driver behaviour, the dynamic simulator provides a safe environment for the testing of driving performance. A simulator study has been carried out where both the complexity of the route layout and a secondary carphone task were included as experimental variables. This study also tested driving performance by introducing a visual target to cue braking reaction. The study revealed a detriment in braking response time, a reduction of speed and an increase of lateral position when using a hands free carphone. It was demonstrated that system intrusion on the driving task was a subtle phenomenon more apparent in braking reaction, psychophysiological stress and subjective mental workload rather than characteristics of the driving task per se.
The second part of the behaviourial work concentrated on the impact of in vehicle information systems, in particular, route navigation systems. Both investigations took the form of real road trials. An experimental comparison between a complex map display and a simple text display for the purpose of route navigation was examined. Drivers' visual behaviour, subjective techniques and psychophysiological measures were particularly revealing.

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Loughborough University
The Elms Elms Grove
LE11 1RG Loughborough
United Kingdom
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