A few years back, I was dragging a trailer down a wide interstate with thick traffic. I was driving in one of the middle lanes when suddenly the traffic parts in front of me, revealing a mattress taking up half my lane. Since I had a trailer, I couldn't just whip my truck into the other lane, and had to move over slower than I would have liked. Thankfully, my trailer managed to miss it, although I don't know if it was by a couple inches, or a couple feet. I've never had more of a pucker factor than that moment, and was on high alert for the rest of the drive that day. I will say it's a good habit to offset your vehicle with the vehicles in the other lanes, because in an instance like that, I didn't have time to double check for clearance.