Sharraxaadda

While driving westbound on I 496 past Waverly Rd overpass I heard a loud pop noise on my left. It sounded like a gun shot. There were no cars in front of me or behind me, but there were two white delivery vans going eastbound that I saw in my rear view mirror. I didn't think much about it until a friend of my wife had the same experience. She was on the expressway as well the same day.