Any time your brakes fail, it seems as if your speeding up. I've had it happen a few times. The worse one was with a 10 yrd. cab over dump truck loaded with gravel. Brakes failed coming down a hill with a stop sign at the end and a T intersection, with a barn on the other side of the crossroad. I slammed the truck into low gear, turned the engine off and let out the clutch. The emergency brake wasn't doing anything. Just before I hit the end, I turned the engine back on. Needed the power steering. Turned to the right and tilted the truck onto its left side wheels. Left half the load on the gravel road before the truck righted itself. I was lucky there wasn't any one traveling on the crossroad. It was a friends dump truck. The county got some donated gravel for their road that day.
Rick