Chunks of tires are making your ride over bridges a little less bumpy. Ken Dunker of the Iowa Department of Transportation, says they’re using discarded tire buffings, or shavings, from tire retread factories to fill in the joint where the bridge meets the pavement. He says they’d been using foam blocks, but those block didn’t anchor very well and would come out of the joint. He says the tire buffings work a lot better because they don’t float out of the joint, and provide some compressibility when the bridge expands. Dunker says the foam joints had become a problem. He says some of the maintenance crews had received a fair number of phone calls from the public reporting things on the road which were the foam blocks. He says the tire shavings don’t float onto the road. Dunker says they’ve been testing the tire buffings as a repair for old bridges, and they now will become the standard. He says they just recently put the tire buffings into their standards for new bridges. Since the tire buffings are a waste product for the tire plants, they’re cheap and cost less than the foam blocks.