Tires are usually seen as a functional part of a vehicle that allows it to smoothly move down the road. As the environmental equation of automobiles becomes a bigger deal, tires are increasingly viewed as a key component that can play a critical role in increasing efficiency and reducing greenhouse gas emissions. Unfortunately, “eco” tires have required a number of trade-offs: higher cost, less grip, and quicker wear.

To address these negatives, Bridgestone Corporation unveiled its latest entry in the category of environmentally friendly tires at the 2010 Chicago Auto Show. The company’s Ecopia EP422 family of tires—the Dueler H/L 422 is designed for trucks, SUVs and crossovers—are all-season low rolling resistance tires made from recycled materials. They each come in five sizes and claim a 36-42 percent improvement in rolling resistance compared to Bridgestone’s typical tires of the same size. From that lower rolling resistance Bridgestone says owners can expect about a 4 percent fuel economy improvement.

According to Bridgestone, the increased fuel efficiency should not only pay back the increased cost of the Ecopia tires, but their entire cost before the end of their 65,000-mile life.

The 422 numbers on the tire have symbolic meaning. That’s Earth Day.