Okay, this has not been tested in reality yet, but one could only think that there has got to be a better way to address this issue of using sand and woodchips as playground surfacing protection materials. The issue has been going round and round due to these materials being questioned as to their ADA accessibility. While not every disabled student can be relocated to a new wheelchair during the school day, some can. And those that cannot be relocated most likely are unable to gain access to the playground structure in the first place.
So, if you are brave you may just take a look at a class of wheelchairs called “all terrain”. These are wheelchairs specifically designed to travel over rough terrain, such as sand and rocks. Google the term – here a link to get you started. http://www.planetmobility.com/store/wheelchairs/power/tracabout/index.html