Research has shown that use of cellular phones does not interfere significantly with the ability to control an automobile except among the elderly, where potentially dangerous lane excursions can occur. However, the effect of cellular phones as a possible distraction has not been investigated. In this study, 151 subjects observed a 25-minute video driving sequence containing 47 situations to which drivers would be expected to respond by manipulation of the vehicle's controls. Each situation occurred equally often under five conditions of distraction: placing a cellular phone call, carrying on a simple cellular phone conversation, carrying on a complex cellular phone conversation, tuning a radio, and no distraction (i.e., none of the proceeding). The radio tuning task was included simply to provide a familiar benchmark. The degree of distraction was measured by comparing responses under each distraction with those occurring in the absence of any distraction. Response was measured in terms of both whether the subject responded and how long it took (with a time penalty for those who did not respond at all). All of the distractions led to significant increases in both the number of situations to which subjects failed to respond and the time it took to respond to them. Complex phone conversations created the greatest distraction and simple conversations the least, with tuning the radio falling in between. Placing a phone call was no more deleterious than a simple conversation in causing situations to go unnoticed, but delayed responses to about the same degree as did complex calls. Relative increase in chances of a highway-traffic situation going unnoticed ranged from approximately 20% for placing a call in simple conversations to 29% for complex conversations. The effect of cellular phone use upon response to highway-traffic situations was the most deleterious for the older age group (i.e., 50-80). Overall, the increase in likelihood that some highway-traffic situation will go unnoticed while calling or conversing on a cellular phone was (for the older group) about twice that of their younger counterparts. Older subjects were no more distracted by radio tuning than the middle-age group (26-49 years) and considerably less than the youngest group (17-25 years). As far as time to respond is concerned, age only effected the placing of cellular phone calls. While a cellular telephone conversation is no more distracting than a conversation of the same intensity with a passenger, the availability of a cellular phone is almost certain to increase significantly the number of conversations in general and the more distracting, intense, business conversation in particular. Older drivers, in particular, should be cautioned against placing calls or carrying on telephone conversations while the automobile is in operation. (A)
Abstract