Texting and driving is the most dangerous form of distracted driving. Dr. Abiodun Akinwuntan of Medical College of Georgia said: "Texting uses four parts of the brain -- visual, verbal, auditory, and motor skills. You have basically pulled all four senses away from driving into texting." Pulling 4 senses away from driving results in Inattention Blindness. Dr. Akinwuntan monitors people in a simulator while they try to drive and text and stated "You can be involved in several near-misses, but it only takes one to make it fatal,"
There's currently a bill (ALERT Drivers Act) in the US Senate requiring states to ban texting and driving or lose federal highway funding. You wouldn't be able to read, write, or send messages. But the bill leaves out looking at emails, so that could still be a danger.
A study from the Virginia Tech Transportation Institute found drivers are 23 times more likely to get into an accident if they're texting or reading emails while driving. There's also an increased risk for simply dialing, talking, or even reaching for a phone.
Link to video and see report. Reporter tries to text & drive in a simulator.