For the most part, drivers agree that texting while operating a vehicle is not something we should be doing. But those same people will make exceptions while at a stop sign or signal light and pick up their phones. Most drivers assume that when their vehicle is stopped they aren’t taking a risk by checking their phone, but research has proven otherwise.

Just looking at one text has been found to tie up your brain for the next 27 seconds (in fact, just asking Siri or Google to do something for you distracts you just the same). The idea is that your brain has disengaged from the activity of driving and has concentrated on writing a text, reading an email, finding that next podcast, or whatever else you might be doing.

If your brain is no longer engaged in driving, you have lost your situational awareness. You don’t see that person about to run across the street between two cars, or the person that’s about to turn right on red without stopping. When the light turns green, or it’s your turn to proceed from the stop sign, you will end up driving blind for the next 27 seconds. These potential hazards that an engaged driver would see go utterly unnoticed by you. 

Nobody wants you to drive down the road for 27 seconds without being aware of your surroundings. Engaged, safe driving means your attention doesn’t leave the road for the entire trip, even when the car might be temporarily stopped. 

University of Utah Study on mental distractions