Overall, the studies concluded that speaking on both hand-held and hands-free phones negatively impacted driving performance, and drivers who engaged in conversation with their passengers experienced similar negative effects
The prevalence of cellular phones, research, and publicized crashes has started many debates related to the role cell phones play in driver distractions.
Daniel Simons, a researcher at the University of Illinois, Urbana, says, “I suppose we can tune out a radio. But driving a car while talking on a cell phone or texting is different. They can seem really effortless but they both use your mind's limited attention resources. You can't do it. Your brain can't do it.” As attentional load increases, attentional capacity gradually diminishes. One frustrated psychologist has argued that the case for multitasking is on a par with 'urban legend', that is, it's a story we like the sound of but is really nonsense. 1