The Freedom Chair is an inexpensive wheelchair that can go through mud and sand, providing true accessibility and easy to built at a cost of less than $200.
“Trails, parks, fields, beaches, gardens…there’s a lot of adventure and life beyond the pavement. Sometimes even the pavement itself is a challenge, thanks to potholes, uneven cuts, and unplowed snow. Getting out and about, on and off road, and participating in the community is important for everyone. We designed the Freedom Chair with the help of hundreds of wheelchair riders and outdoor enthusiasts to make an off-road wheelchair unlike any other.”
You can watch the MIT engineer Amos Winter present the mechanics at this TED conference:
Freedom For Sustainability 