Roadtrip Bladder 

Being able to hold it for long periods of time.

"do you need to use the restroom?" "naw I have a Roadtrip Bladder."

Roadtrip Bladder by Daten-Shi May 12, 2015

Road trip bladder 

When your on a road trip and your bladder expands to twice its size and urination lasts a minute or more.

My piss lasted at least a minute after that 6 hour bus ride, I had total road trip bladder

Road trip bladder by Ohnoidied January 13, 2011