I'm not ashamed. In fact I'm a strong advocate of having a potty in your car for kids under 7. Yes 7. I am not really at the stage where I can send a kid to the bathroom alone, frankly that stage scares me even more.
I am a firm believer that new genitalia should never contact surfaces where hundreds of thousands of people have been. Well I hit this Car Potty Epiphany when we ended up at the WORST possible place to go to the bathroom- the mall. The disgust that rushed over my body was indescribable. I would like to add that I had a new baby strapped to me in a Bjorn... before all the trifling comments post, put yourself in a dirty bathroom with a toddler and a new baby and no family bathroom. So I just let her dump herself (much to her frustration & dismay). In fact she held it and made such a mess that I had buy new clothes and I changed her in the van. To this day I would have still made the same decision rather than find a way to put her on that deplorable toilet and not dropping my other baby. That day I VOWED never to be unprepared again. I've been happy ever since.
So my kids just unbuckle now. I pull over and they go. We clean it up. I throw it in the trash and we keep moving. I am not frantically driving around for a restroom EVER and they can go with the flow of their body telling them when they need to "use it".
My car potty has saved numerous friends and... Secretly I've peed in it in a Target parking lot a few times when I didn't want to take ALL the kids into the bathroom or leave them in the car illegally.
Disinfecting Spray and even toilet bowl cleaner is perfect for keeping car odor down and germs to a minimum.
Lysol spray is always a handy back up for the huge disasters that happen more often than not.
Paper towels are awesome for clean up. If we are out of Car TP and baby wipes I tear these into quarters. I also recommend placing half a paper towel in the actual bowl after you clean up to "catch" and absorb the next time. It's conceptually like a "diaper" for the bowl and makes clean up easier.
Because I'm a self proclaimed germaphobe I KEEP hand sanitizer in the cup holders.
An air freshened sits by the potty because wowzers... Kids have no shame.