BMW now ship the majority of their cars with Run-Flat (anti-puncture) types the are harder than normal types but are pretty indestructable. you dont want 3 inch tread on a tyre as your car would feel like its on jelly (jello) as there is little structural strength in the tread of tyre.

I doubt that a three inch tread would maintain the weight of the vehicle to permit a three inch clearance from the road. And it would wear out very quickly. If you're goung to get paranoid about nails on th road a more impractical fantastic solution would be to have a powerful electromagnet mounted on the front of the car and be careful not to approach sewer covers or fire hydrants too closely.

I almost can't remember the last time I had a flat tire.

I think tires are pretty good now, and roads are much 'cleaner' than in decades past.

Other readers have noted that your proposal to thicken the tread is problematic. I agree.

I do know that people have been designing airless-tires since at least the 70's and I've actually seen them on new skid-loaders (which always seem to be getting flats in my experience). But I just think they're not yet a viable compromise between give and firmness.

I like this Idea. I think it is a creative and interesting way to solve the problems that we face on the road!

If a conventional tire were filled with an open-celled foam (like the white foam that coffee cups are made of), you could still pump air into the open cells, but if the tire went flat, it wouldn't deflate much. hrench is right that tires don't go flat much any more, but a low-cost addition to increase safety if a flat happens would be worth it.

This kind of tire would be nearly impossible to mount on a wheel. You would have to buy them either as a wheel and tire combo that you cannot change out unless you buy the wheel and tire, or get a two piece wheel...

I like your thinking, but look up "tweel" and see what that is about.