ASSOCIATION BETWEEN CELLULAR-TELEPHONE CALLS AND MOTOR-VEHICLE COLLISIONS

Background Because of a belief that the use of cellular telephones whi le driving may cause collisions, several countries have restricted the ir use in motor vehicles, and others are considering such regulations. We used an epidemiologic method, the case-crossover design, to study whether using a cellular telephone while driving increases the risk of a motor vehicle collision. Methods We studied 699 drivers who had cel lular telephones and who were involved in motor vehicle collisions res ulting in substantial property damage but no personal injury. Each per son's cellular-telephone calls on the day of the collision and during the previous week were analyzed through the use of detailed billing re cords. Results A total of 26,798 cellular-telephone calls were made du ring the 14-month study period. The risk of a collision when using a c ellular telephone was four times higher than the risk when a cellular telephone was not being used (relative risk, 4.3; 95 percent confidenc e interval, 3.0 to 6.5). The relative risk was similar for drivers who differed in personal characteristics such as age and driving experien ce; calls close to the time of the collision were particularly hazardo us (relative risk, 4.8 for calls placed within 5 minutes of the collis ion, as compared with 1.3 for calls placed more than 15 minutes before the collision; P<0.001); and units that allowed the hands to be free (relative risk, 5.9) offered no safety advantage over hand-held units (relative risk, 3.9; P not significant). Thirty-nine percent of the dr ivers called emergency services after the collision, suggesting that h aving a cellular telephone may have had advantages in the aftermath of an event. Conclusions The use of cellular telephones in motor vehicle s is associated with a quadrupling of the risk of a collision during t he brief period of a call. Decisions about regulation of such telephon es, however, need to take into account the benefits of the technology and the role of individual responsibility. (C)1997, Massachusetts Medi cal Society.