Driver Reaction Time to Avoid Collisions During a Mobile Phone Conversation

The overall objective of this work is to contribute to knowledge concerning if, when and how much mobile phone use affects the safety of driving. The work entails analysing driving performance while using different mobile equipment in different road configurations and in the specific case of a critical driving situation. Three different scenarios were implemented in the driving simulator of the Inter-Universities Research Centre for Road Safety (CRISS) at Roma Tre University: an urban road, a two-lane rural road and a highway. Thirty drivers were asked to answer a phone call while driving, using different mobile equipment: hand-held, hands-free and hands-free voice-activated cellular phone. The effects of using the mobile phone were also compared to the baseline condition (no phone conversation). Driving performance, under car-following conditions, were collected and statistically analysed when a sudden braking of the leading vehicle occurred. The main results demonstrated that the driver’s speed generally reduced during the phone call, as a compensatory action to the decrease in the driver’s reaction capability, as shown by the generally increased reaction time, especially under certain driving conditions (urban road, along tangent, using hand-held mobile device). This study provided an investigation on the effects of using a mobile phone while driving; highlighted the worst combinations of the variables investigated; and demonstrated that some reductions in driving performance were revealed under critical road situations, especially in the urban environment, even when using mobile equipment that is permitted by the regulations of several countries.