LBM,
Here is the link to one of the pages for the Open Road tires. check out some of the other info on other pages too.
http://www.airfreetires.com/OpenRoad/Default.htm
The newest tires are made of a new compound (the HR tires), the same sort of stuff that the elastomers in shocks are made from.
They are heavier than regular tires, but for someone who commutes to work by bike, they will provide the ultimate reliability. There have been many discussions on Alt.rec.bicycles.recumbent on the value of a heavier tire (everyone wants to go fast) but many are setteling for reliability.
Airfreetires has made tires for larger rims, but now they are about to release them for the thinner rims, the 16-18mm used on many recumbents. They are starting with a 20", then will have a 26". The Open Road is a new shape they hope will excell in road use.
I know Sheldon Brown doesn't think much of airless tires in general, but a lot of his articals are old, and he may not be familiar with the newest technology in airfree design.
Tom Balmer