I witnessed a multiple vehicle accident caused by some bozo transporting his mattress on top of a mini-van secured by bungee cords. It came off the vehicle in front of me and I was able to change lanes without problems, the guy behind me dodged right and pushed the guy in his blind spot into the guy in his blind spot, then the first guy over corrected and spun into the right lane and got t-boned before hitting the guard rail. The guy driving the van who lost the mattress either didn't notice or didn't care, I'm guessing he didn't care.
I've always told myself if I'm in the situation again I'll take my chances hitting a mattress rather than make a knee jerk reaction and endanger everybody else on the road. I figured the damage would be more like a cracked air dam, I never would have guessed a mattress could get wrapped around a drive shaft like that. I'm always careful to stay far behind or far ahead when I see a mattress on the roof of a car.