Penalize the result, not something that "could" result in dangerous driving. If someone causes a wreck or runs off the road because they were distracted, it shouldn't matter whether they were distracted because they were texting, putting on makeup, handing a bottle to their kid in the back seat, or freaking out because they dropped their Big Mac in their lap. If you want to reduce avoidable wrecks, make the penalty for causing an avoidable wreck such that people actually focus on driving safely.