In this age we are very able beings. We have the ability to multitask or better -task switch.
With mobile phone in one hand and something else in the other we find ourselves doing multiple things. Driving is one of the dangers of task switching.
Task Switching is something we do without much thought, we can cook dinner, watch tv and work on our computer at the same time but not really the same time but rather task switching.
Focus is blurred when we change our task but more importantly we can do more things in less time.
Just remember trying to do something other than driving is dangerous, so when you task switch make sure no one is in danger.