The cause of traffic accidents when drivers use car phones and the functional requirements of car phones for safe driving

This paper reports how driving behaviour is affected by the use of mobile phones. We measured the reaction time (RT) in various conditions to detect what kind of effects mobile phone use has in the face of accidents. It is important to study RT in driving because the stopping distance of the car varies with the driver's RT. For this study, we prepared a system which measures the time from when a lamp mounted on the windshield of the car lights up to when the driver steps on the brake pedal. The RT was measured under three conditions: a) During a conversion using a handset b) During a manual task with a handset c) During a manual task with a handset, with eyes on the road ahead. The results of our experiments showed that the RT was prolonged unexpectedly when the driver took his eyes off the road to make or to take a phone call. The main effect of the car phone appears to be on the distraction of visual attention, rather than on physical or mental demand in operating the phone and engaging in a conversation.