For those with no bathroom access during travel mode.

TxGearhead wrote:
We can squeeze by to get to the bathroom, but I usually just open 2 truck doors and water the road shoulder, or a parking lot, or...

For much of my life, I would kick the water out of tire. But sometime in the late '90s some jurisdictions decided that if a woman or child could see, it was a sex crime.
Stay inside, use a fast-food cup. Dump like melted ice before you pull out.