Alternative walk-off mat materials

I've been asked to evaluate a recycled rubber entry system under the "carpet tile" concept. I think it might fall short of the credit intent, but wondered if anyone else has experience with a system like this. The system is recessed, however, the rubber mat is glued down. It is constructed of strips of rubber tires, turned vertically and stacked side by side creating a fairly solid rubber mat. The top edge of each rubber strip is buffed until fuzzy, but I wouldn't describe it as having "high void volume" to trap dirt. Any thoughts? This project is located in the Midwest (USA), so they will experience all ranges of weather.