Earlier today I was driving behind a double-trailer dump truck configured something like this:
As we approached a red light, the driver obviously applied the brakes, and for the last 50 or so feet before coming to a stop, the rear wheels of the rear trailer were all very obviously locked up as evidenced by clouds of smoke and a nice skid mark from all 4 tires on that axle.
This was during normal driving conditions. I don't think the driver was making any kind of emergency stop.
Are the rear wheels locking up due to some malfunction, or is this perhaps happening simply because the rear trailer was possibly unloaded?
Out of an abundance of caution I made sure to leave an extra comfortable distance. However, other than the spectacular smoke and skidmarks, the vehicle appeared to be under control. Is there any danger to either the truck or to other vehicles (me) when this happens?