I'm going to assume you don't live in an area with traffic half as bad as Atlanta or Beijing then ;)
Doing that in rush hour just means some jackass *WILL* cut into your lane and try to get in front of you, meaning you'll be held up longer and so will the lane that jackass was in as he's too stupid, hasty, and narrow-minded to realize constantly changing lanes is only a method for self-gratification rather than accomplishing anything remotely productive. I'd know, I have far too much experience in Atlanta traffic -.-