Pulling A Peterbilt with the Brakes Locked

[INTERNATIONALPOWER]

Pulling a Peterbilt COE with brakes locked. YouTube - My Truck Pulls a Pete

It might of help if the breaks were unlocked.

 

[F350DRW1]

Seems like the pass. side front's were stuck, others were rolling. Slack adjustors may be a little tight on that wheel.

 

[bushpilot]

so if the brakes are on, only ONE axle is locked ?
I would have expected both rear axles to be locked.