Oh yes, by all means, post at car-seat.org. I'm about to go to Lifesavers and sometimes they have cool ideas (like, a pool noodle used to be 57" tall, you can hold it up and see if kids are that tall and can ride without a booster). Maybe you have a state Safekids coalition, they might have handouts and coloring books and stuff specific to your state. If you can get someones minivan seat somehow set up (or if your Sk has a seat to borrow), then you can make kids try the 5-step test (butt all the way back, belt low on hips, centered on shoulder, knees bent over the edge, sit that way the whole trip), that's kind of a fun tool that kids end up knowing whether they are safe in a car without a booster, too.
Oh, look around at
www.carseat.org, too, I think they have handouts and flyers that are free .pdfs, like the 5 step test used to be number 630, but I'm too lazy to google right this minute, lol.