Effect of the intensity of wireless telephone conversations on reaction time in a braking response

Recently, concern has grown about the extent to which wireless telephone use by motor vehicle drivers constitutes a threat to traffic safety. This experiment investigated the effect of the intensity of wireless telephone conversations on reaction time (RT) for a braking response. Using a laboratory station to mimic the foot activity in driving, 16 adults were instructed to release the accelerator pedal and depress the brake pedal as quickly as possible following the activation of a red brake light. Mean RT was measured for 5 conditions which manipulated the intensity of a conversation, i.e., demand for attention, conducted on a wireless telephone. Analysis indicated that wireless telephone use caused a decrement in RT, however, there was no significant effect associated with intensity of the conversation across intensity.