Imagine you're in your car. You've your music playing and you see someone next to you at a stop light smoking a cigarette. You suddenly have an urge to smoke, but luckily for you, you've your handy dandy vaporizer! You continue listening to your music as you are driving down the road; you start using your device and all of a suddenly you can't see out of your windshield because of all the vape clouds you created, and then BOOM! You crashed.
Vaping while driving is a very dangerous thing to do. Not only can it distract you and block your view but if you've a cheap device, it can drip and leak e-juice onto you and you could easily get hurt from not being able to do anything since you're driving.
Also, if you're out of juice or out of battery charge, that requires two hands but you need at least one (preferably both) to drive.
There are many dangers that come along with vaping while driving. If you're going to vape while you drive, always make sure that your window is cracked. It'll take all the vapor out of your vehicle so that you're able to see better while you drive. If you're driving and a cop sees that your car is filled with smoke (in this case vape clouds) then there is a very good chance that he will pull you over. Any obstruction to your view can and will get you in trouble with the law.
Long story short, don't vape while you drive. I've been an avid vapor for a little over 4 years and I can honestly and proudly say that I've never vaped while driving and I never vaped in a friends car while they were driving either.