Funding organisation: Continental Tyres
As mobile office technology becomes more advanced, drivers have increased opportunity to process information ‘on the move’. Although speech-based interfaces can minimize direct interference with driving, the cognitive demands associated with such systems may still cause distraction. This study compared the effects on driving performance of a simulated, in-vehicle, ‘E-mail’ message system. E-mails were either system-controlled or driver-controlled. The LADS was used to test 19 participants on a car following task. Virtual traffic scenarios varied in driving demand. Drivers compensated for the secondary task by adopting longer headways, but showed reduced anticipation of braking requirements and shorter time-to-collision. Drivers were also less reactive when processing E-mails, demonstrated by a reduction in steering wheel inputs. In most circumstances, there were advantages in providing drivers with control over when E-mails were opened. However, during periods without E-mail interaction in demanding traffic scenarios, drivers showed reduced braking anticipation. This may be a result of increased cognitive costs associated with the decision making process when using a driver-controlled interface, where the task of scheduling E-mail acceptance is added to those of driving and E-mail response. Actual or potential applications of this research include the design of speech-based, in-vehicle messaging systems.