I used to know this but, does anyone know the flashpoint of gasoline?
From what I remember it's not all that dangerous in the real world. A full can with little to no vapor room is pretty safe (well within reason) but what I'm getting at is a full can in the cab and a window open is enough to make it pretty benign.
Now in a accident, well that's a different story, but let's face it driving its self is pretty risky so why not add a little excitement:boom:
All that being said, it's better safe then sorry right?
So it's just best to fill the can when you know you will be testing the limits of your vehicles range.