As far as I know they're considering adding noisemakers to them, for the benefit of pedestrians.
Dogs of all sizes enjoy chewing on pliable noisemakers made from rubber or latex.
The audiologist observes startle responses and motor reflex changes in the child as various noisemakers are employed to elicit these responses.
But it's also great to get the kids involved by having them decorate the noisemakers, and they'll work just as well either way.
These noisemakers are really easy to use; just grab them by the handle and shake.