Weight transfer and traction has a lot mote to do with stopping than the design of the brake system. It's not uncommon for the front brakes on any vehicle to do 70% or more of the stopping, due to weight being transferred forward during a stop. Add to that the fact that truck brakes are designed to handle a fully loaded vehicle, and rear wheel lockup when unloaded is pretty much a given unless some finesse is applied while stopping. "Finesse" and "panic" don't always go together, but the final factor is always "traction".
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!