Was travlling Westbound I-30 at approximately 80mph when I spied a muffler on the shoulder, against the construction area restraining wall. I swerved to avoid it, but the truck in the next lane was only about 18-inches away, and I caught the tip of it. Fortunately, it alterned neither my trajectory, nor my velocity. Until I slowed to 70 coming up on traffic ahead. That's when the tire blew. I pulled over at a safe spot betwix the interstate and an entrance ramp, and Tony and I changed the flat and were moving again 9 minutes later. (Photographs pending, the camera is in the car which is in the shop - yes, Tony visually documented everything.) The miniature "doughnut" tire was low on air, and I had to drive to three different places around the greater Grand Prairie area to find an operational air machine (in Boyd they're free, and I'm expecting a $.50 refund check in the mail in seven to ten days from the first failed machine). As I lead a charmed life, and this was two negative incidents in a single day, I'm expecting the next six months to two years to be generally incident-free.