D.W.
You can bring the potty along though!
I have a potty, clorox wipes, puppy pads and plastic grocery bags in a bag in the back of my small suv. When my daughter says she needs to go I can pull the car over, line the potty with a puppy pad (I cut them in thirds), let her go, lift out the pad and put it in the grocery bag and toss it. Wipe out the potty and you are good to go. The pads have been a life-saver! No muss, no fuss. They soak up urine great and catch any solids so I don't have to touch or deal with a mess while we are on the go.