Either that - or folks were hitting the release button in the cab and sliding the 5th without realizing it, Happens enough times, company disconnects it.
Unrelated, but my tractor has a black knob on the dash that says "Pull To Uncouple Trailer". On the dash behind it is what seems like some very wise advice: Do Not Operate While Vehicle Is In Motion. I've never pulled it but I'm guessing it's disconnected. I've often wondered why a tractor would have that. It seems like it would only be useful for a yard tractor, but maybe there's some other use I'm unaware of.
That kingpin release is very handy. It keeps you from having to manually release the kingpin. Saves wear and tear on your shoulders.
That kingpin release is very handy. It keeps you from having to manually release the kingpin. Saves wear and tear on your shoulders.