Q: How does cellphone use affect driving performance?
A: An Institute review of more than 120 cellphone studies, about half of which were experimental studies using driving simulators or vehicles instrumented with video cameras, sensors, and other equipment, found that nearly all reported that some measures of driver performance were affected by the cognitive distractions associated with cellphone tasks. Phone conversation tasks typically increased reaction times and travel speeds and increased lane deviations and steering wheel movements. Statistical analyses that aggregated the results of 33 studies and 23 studies, respectively, reported similar findings. Some studies have found that older drivers' performance is more affected by cellphone tasks, particularly their reaction time. Few studies included drivers younger than 18, and evidence is mixed on the effects of phone use for teenage drivers compared with adult drivers. Findings also are mixed on whether driving performance while talking on a cellphone improves with practice. Some simulator studies suggest that the negative impact of phone use on driving performance may lessen with experience. Other simulator research has found no change in performance with practice.

Q: Does using a cellphone while driving increase crash risk?
A: Yes. Two controlled studies link talking on a cellphone directly to increased crash risk. A 2005 Institute study of drivers in Western Australia found cellphone users four times as likely to get into crashes serious enough to injure themselves. The study used cellphone billing records to verify phone use of crash-involved drivers. Increased risk was similar for males and females, drivers younger than 30 and those 30 and older, and handsfree and hand-held phones. The findings were consistent with 1997 research that showed phone use among Canadian drivers was associated with a fourfold increase in the risk of a property damage crash. The Canadian study also used cellphone billing records to verify phone use of drivers.