I would probably give Miss Piggy another week to clean up her act, if she doesn't then she probably never will. I'd rather lose the pleasure of riding in her garbage truck and enjoy another day of driving my Prius alone!
It sounds like she knows it's a problem. I would say that opens the door for you to be a little pushier than etiquette might normally allow. I don't think you have to take that for a week, or even a day, just come right out and tell her to clean it up. As for giving rides, I'm in the "I prefer to drive" category when it comes to sharing rides. I'd go a step further and say that I'd prefer people to ride in my car than for me to ride in their SUV. Yes, I'd be putting more miles on than them, but using less gas, and lower emissions. I can't really rideshare on my bike though, so I don't do much of that In a related story, I've been reading my Grandfather's autobiography, and every time he mentions traveling during his youth (throughout and after the great depression) he mentions that he hitchhiked to get places. Maybe the killer gas prices will bring back hitchhiking in a big way!