Or you can make your own wheelchair logo thingie to hang from the rear view mirror.
Seriously, I think there should be more stringent standards for who gets to park in those spaces. Here in my town I've seen perfectly able-bodied guys park giant $90,000 diesel 4X4 pickups in those spaces and stroll on into the grocery store no different from anyone else. There is a racket going on with the disability system. One of my close friends is a veteran who got seriously injured in the first Gulf War; he's been fighting for more than 20 years on his case and only making progress in recent years. He's seen other guys who barely got so much as a scratch get 100% thanks to the right connections, and these guys are still working full time -even owning their own businesses. It makes a mockery of people who have legit, serious physical challenges.
Important sign making tip: never use the word "handicapped" in any wheelchair access sign. Recently we had a window graphics project for a local employment organization that required labeling and way-finding directional graphics for the entrance with a wheelchair ramp and motorized door. The client wanted us to use the verbiage "handicapped access" along with the wheelchair icon. The client didn't understand the term "handicap" is offensive in its historical roots. Even the term "disabled" has a negative connotation. Everyone understands what the wheelchair icon means. So we agreed on the solution being using the wheelchair icon and "Accessible Entrance" for the verbiage.