Talking on the phone in the car is the distraction, not holding the phone. Certainly texting while driving is a horrific idea. Then again we should consider any activity other than driving a punishable offense whiling operating a vehicle, ie shaving, putting on makeup up, reading the morning paper, eating, drinking beverages, smoking, and I have seen all of these activities attempted while driving. All of these activities have the ability to distract a driver enough to cause an accident. Inattention while operating a vehicle is easily the cause of most accidents. Even the act of running through all the activities you plan on doing at any given time while operating a vehicle can cause the distraction.
Most people can remember being in car driving, while thinking about other things. A few minutes later thinking, "Wow, I don't remember how I got here". This is because the cognitive conscious parts of your brain require 100 percent of your attention while driving. When you attempt to multitask while driving, your Brain hands off the driving duties to the Unconscious part of your brain, because you generally have done that task repetitively. While your unconscious brain can generally manage driving duties like staying between the lines on a straight road, it can NOT manage or act properly when faced with a sudden tasks, like a vehicle making sudden unanticipated maneuvers, a Traffic light changing to red, somebody running a stop sign etc.
Put the phone down, and start paying attention while driving. Most humans don't even realize the complexities and cognitive abilities required while driving, as it is something we do everyday so we rationalize (wrongly) how easy the task of driving is.