Bout 5 years ago I was west bound on I-10 in New Orleans slightly behind and beside a truck pulling a speedboat on a trailer. It was night and I couldn't help to notice the glow and shower of sparks emitting from the boat trailer axle/wheel area. Seems he hadn't greased his trailer bearings in a while. Well I immediately sped up to get his attention to let him know he had a big problem. I got his attention and he nodded and started to slow and try get to the shoulder of the road. The wheel failed on the trailer as he tried to get over to the shoulder. Sparks and chaos everywhere! The trailer dug in the road and eventually decoupled from his bumper, slewing to the right and trying to dump the boat on the road...thank god for safety chains. If that trailer had come totally loose and got sideways in traffic, I shudder to think of the consequences.