Even if you're not at the legal blood alcohol concentration (BAC) limit of .08%, drinking any amount and then driving has a negative effect on your ability behind the wheel. At .02% BAC, drivers experience a decline in visual functions, such as rapid tracking of a moving target, as well as worsened ability to perform two tasks at the same time. Higher BAC levels result in a further decline of skills, including an inability to recognize turn signals, maintain lane position, and a delay in braking response.
Distracted driving has three components: visual (taking your eyes off the road), manual (taking your hands off the wheel), and cognitive (taking your mind off of driving). This includes activities like eating, watching a movie, or even using an in-vehicle navigation system.
The most common form of distracted driving – texting while driving – combines all three components at once, much like driving while intoxicated does. Particularly troubling texts and phone calls may also cause a driver to become angrier or more depressed, causing additional distraction. Even for seemingly harmless messages, consider this: the average text takes about five seconds to send. Traveling at 55 mph, that's like going the length of an entire football fieldwith your eyes closed.
Source: The Zebra, June 9, 2017