You should never play Pokémon GO when you're behind the wheel of a car - that much is obvious. Just like sending a text or taking a phone call, it's a distraction which dramatically increases the chances of you getting into an accident. Niantic has even gone as far as to include a warning message in the game which pops up when it senses that you're travelling at the kind of speed only possible when inside an automotive vehicle.
However, for those who continue to try and catch 'em all whilst driving, consider this commercial from Esurance as a warning. Not only do you run the risk of seriously hurting yourself and others, you could end up looking as stupid as the people featured in the video above.
Explaining to the police officer you just back-ended at the traffic lights that you were trying to catch a rare virtual monster isn't going to make you look particularly clever. Just ask this guy.
Thanks to Arjun for the tip!